diff --git a/analytics/tests/test_stats_views.py b/analytics/tests/test_stats_views.py
index 2591a40044..97959a0fc0 100644
--- a/analytics/tests/test_stats_views.py
+++ b/analytics/tests/test_stats_views.py
@@ -10,7 +10,8 @@ from analytics.models import FillState, RealmCount, StreamCount, UserCount
 from analytics.views.stats import rewrite_client_arrays, sort_by_totals, sort_client_labels
 from zerver.lib.test_classes import ZulipTestCase
 from zerver.lib.timestamp import ceiling_to_day, ceiling_to_hour, datetime_to_timestamp
-from zerver.models import Client, get_realm
+from zerver.models import Client
+from zerver.models.realms import get_realm
 
 
 class TestStatsEndpoint(ZulipTestCase):
diff --git a/analytics/tests/test_support_views.py b/analytics/tests/test_support_views.py
index a162edfcbf..922b1bd79a 100644
--- a/analytics/tests/test_support_views.py
+++ b/analytics/tests/test_support_views.py
@@ -23,16 +23,8 @@ from zerver.actions.realm_settings import do_change_realm_org_type, do_send_real
 from zerver.actions.user_settings import do_change_user_setting
 from zerver.lib.test_classes import ZulipTestCase
 from zerver.lib.test_helpers import reset_email_visibility_to_everyone_in_zulip_realm
-from zerver.models import (
-    MultiuseInvite,
-    OrgTypeEnum,
-    PreregistrationUser,
-    Realm,
-    UserMessage,
-    UserProfile,
-    get_org_type_display_name,
-    get_realm,
-)
+from zerver.models import MultiuseInvite, PreregistrationUser, Realm, UserMessage, UserProfile
+from zerver.models.realms import OrgTypeEnum, get_org_type_display_name, get_realm
 from zilencer.lib.remote_counts import MissingDataError
 
 if TYPE_CHECKING:
diff --git a/analytics/views/installation_activity.py b/analytics/views/installation_activity.py
index 5144e969c8..58f4aabc36 100644
--- a/analytics/views/installation_activity.py
+++ b/analytics/views/installation_activity.py
@@ -25,7 +25,8 @@ from analytics.views.activity_common import (
 from analytics.views.support import get_plan_type_string
 from zerver.decorator import require_server_admin
 from zerver.lib.request import has_request_variables
-from zerver.models import Realm, get_org_type_display_name
+from zerver.models import Realm
+from zerver.models.realms import get_org_type_display_name
 
 if settings.BILLING_ENABLED:
     from corporate.lib.analytics import (
diff --git a/analytics/views/stats.py b/analytics/views/stats.py
index 9366945151..a12873bf55 100644
--- a/analytics/views/stats.py
+++ b/analytics/views/stats.py
@@ -36,7 +36,8 @@ from zerver.lib.response import json_success
 from zerver.lib.streams import access_stream_by_id
 from zerver.lib.timestamp import convert_to_UTC
 from zerver.lib.validator import to_non_negative_int
-from zerver.models import Client, Realm, Stream, UserProfile, get_realm
+from zerver.models import Client, Realm, Stream, UserProfile
+from zerver.models.realms import get_realm
 
 if settings.ZILENCER_ENABLED:
     from zilencer.models import RemoteInstallationCount, RemoteRealmCount, RemoteZulipServer
diff --git a/analytics/views/support.py b/analytics/views/support.py
index 06ee893051..d16ef66e48 100644
--- a/analytics/views/support.py
+++ b/analytics/views/support.py
@@ -40,9 +40,8 @@ from zerver.models import (
     Realm,
     RealmReactivationStatus,
     UserProfile,
-    get_org_type_display_name,
-    get_realm,
 )
+from zerver.models.realms import get_org_type_display_name, get_realm
 from zerver.models.users import get_user_profile_by_id
 from zerver.views.invite import get_invitee_emails_set
 
diff --git a/corporate/lib/stripe.py b/corporate/lib/stripe.py
index df861af806..51b76b29ec 100644
--- a/corporate/lib/stripe.py
+++ b/corporate/lib/stripe.py
@@ -50,7 +50,8 @@ from zerver.lib.send_email import (
 from zerver.lib.timestamp import datetime_to_timestamp, timestamp_to_datetime
 from zerver.lib.url_encoding import append_url_query_string
 from zerver.lib.utils import assert_is_not_none
-from zerver.models import Realm, RealmAuditLog, UserProfile, get_org_type_display_name, get_realm
+from zerver.models import Realm, RealmAuditLog, UserProfile
+from zerver.models.realms import get_org_type_display_name, get_realm
 from zerver.models.users import get_system_bot
 from zilencer.lib.remote_counts import MissingDataError
 from zilencer.models import (
diff --git a/corporate/lib/support.py b/corporate/lib/support.py
index eb4ffa5c80..4076245993 100644
--- a/corporate/lib/support.py
+++ b/corporate/lib/support.py
@@ -14,7 +14,8 @@ from corporate.models import (
     ZulipSponsorshipRequest,
     get_current_plan_by_customer,
 )
-from zerver.models import Realm, get_org_type_display_name, get_realm
+from zerver.models import Realm
+from zerver.models.realms import get_org_type_display_name, get_realm
 from zilencer.lib.remote_counts import MissingDataError
 
 
diff --git a/corporate/tests/test_stripe.py b/corporate/tests/test_stripe.py
index 4653c3594f..35f98e12cc 100644
--- a/corporate/tests/test_stripe.py
+++ b/corporate/tests/test_stripe.py
@@ -102,7 +102,8 @@ from zerver.lib.remote_server import send_server_data_to_push_bouncer
 from zerver.lib.test_classes import ZulipTestCase
 from zerver.lib.timestamp import datetime_to_timestamp, timestamp_to_datetime
 from zerver.lib.utils import assert_is_not_none
-from zerver.models import Message, Realm, RealmAuditLog, Recipient, UserProfile, get_realm
+from zerver.models import Message, Realm, RealmAuditLog, Recipient, UserProfile
+from zerver.models.realms import get_realm
 from zerver.models.users import get_system_bot
 from zilencer.lib.remote_counts import MissingDataError
 from zilencer.models import (
diff --git a/docs/tutorials/new-feature-tutorial.md b/docs/tutorials/new-feature-tutorial.md
index 6345753fe4..0e34ee02fa 100644
--- a/docs/tutorials/new-feature-tutorial.md
+++ b/docs/tutorials/new-feature-tutorial.md
@@ -35,7 +35,7 @@ organization in Zulip). The following files are involved in the process:
 
 **Backend**
 
-- `zerver/models/__init__.py`: Defines the database model.
+- `zerver/models/realms.py`: Defines the database model.
 - `zerver/views/realm.py`: The view function that implements the API endpoint
   for editing realm objects.
 - `zerver/actions/realm_settings.py`: Contains code for updating and interacting with the database.
@@ -73,7 +73,7 @@ organization in Zulip). The following files are involved in the process:
 ### Adding a field to the database
 
 **Update the model:** The server accesses the underlying database in
-`zerver/models/__init__.py`. Add a new field in the appropriate class.
+`zerver/models/realms.py`. Add a new field in the appropriate class.
 
 **Create and run the migration:** To create and apply a migration, run the
 following commands:
@@ -185,10 +185,10 @@ task of requiring messages to have a topic, you can [view this commit](https://g
 
 First, update the database and model to store the new setting. Add a new
 boolean field, `mandatory_topics`, to the Realm model in
-`zerver/models/__init__.py`.
+`zerver/models/realms.py`.
 
 ```diff
- # zerver/models/__init__.py
+ # zerver/models/realms.py
 
  class Realm(models.Model):
      # ...
@@ -205,7 +205,7 @@ is the field's type. Add the new field to the `property_types`
 dictionary.
 
 ```diff
- # zerver/models/__init__.py
+ # zerver/models/realms.py
 
  class Realm(models.Model)
      # ...
diff --git a/puppet/zulip/files/nagios_plugins/zulip_app_frontend/check_send_receive_time b/puppet/zulip/files/nagios_plugins/zulip_app_frontend/check_send_receive_time
index bcf3842ef9..7ff669e565 100755
--- a/puppet/zulip/files/nagios_plugins/zulip_app_frontend/check_send_receive_time
+++ b/puppet/zulip/files/nagios_plugins/zulip_app_frontend/check_send_receive_time
@@ -66,7 +66,7 @@ django.setup()
 
 from django.conf import settings
 
-from zerver.models import get_realm
+from zerver.models.realms import get_realm
 from zerver.models.users import get_system_bot
 
 states = {
diff --git a/tools/generate-integration-docs-screenshot b/tools/generate-integration-docs-screenshot
index e00d5fb30e..1f471961b1 100755
--- a/tools/generate-integration-docs-screenshot
+++ b/tools/generate-integration-docs-screenshot
@@ -50,7 +50,8 @@ from zerver.lib.storage import static_path
 from zerver.lib.streams import create_stream_if_needed
 from zerver.lib.upload import upload_avatar_image
 from zerver.lib.webhooks.common import get_fixture_http_headers
-from zerver.models import Message, UserProfile, get_realm
+from zerver.models import Message, UserProfile
+from zerver.models.realms import get_realm
 from zerver.models.users import get_user_by_delivery_email
 
 
diff --git a/tools/semgrep-py.yml b/tools/semgrep-py.yml
index a83ac442f8..dad2e7bf91 100644
--- a/tools/semgrep-py.yml
+++ b/tools/semgrep-py.yml
@@ -50,7 +50,7 @@ rules:
       - pattern-not: from zerver.models import filter_pattern_validator
       - pattern-not: from zerver.models import url_template_validator
       - pattern-not: from zerver.models import generate_email_token_for_stream
-      - pattern-not: from zerver.models import generate_realm_uuid_owner_secret
+      - pattern-not: from zerver.models.realms import generate_realm_uuid_owner_secret
       - pattern-either:
           - pattern: from zerver import $X
           - pattern: from analytics import $X
diff --git a/tools/test-api b/tools/test-api
index 8a371641e9..0eea5f7446 100755
--- a/tools/test-api
+++ b/tools/test-api
@@ -36,7 +36,7 @@ with test_server_running(
     from zerver.actions.users import change_user_is_active
     from zerver.lib.test_helpers import reset_email_visibility_to_everyone_in_zulip_realm
     from zerver.lib.users import get_api_key
-    from zerver.models import get_realm
+    from zerver.models.realms import get_realm
     from zerver.models.users import get_user
     from zerver.openapi.javascript_examples import test_js_bindings
     from zerver.openapi.python_examples import (
diff --git a/zerver/actions/create_realm.py b/zerver/actions/create_realm.py
index a87b851bd3..ca38c889a6 100644
--- a/zerver/actions/create_realm.py
+++ b/zerver/actions/create_realm.py
@@ -31,9 +31,8 @@ from zerver.models import (
     RealmUserDefault,
     Stream,
     UserProfile,
-    get_org_type_display_name,
-    get_realm,
 )
+from zerver.models.realms import get_org_type_display_name, get_realm
 from zerver.models.users import get_system_bot
 from zproject.backends import all_implemented_backend_names
 
diff --git a/zerver/actions/realm_domains.py b/zerver/actions/realm_domains.py
index ed03e9fd0b..1ea401beae 100644
--- a/zerver/actions/realm_domains.py
+++ b/zerver/actions/realm_domains.py
@@ -4,14 +4,8 @@ from django.db import transaction
 from django.utils.timezone import now as timezone_now
 
 from zerver.actions.realm_settings import do_set_realm_property
-from zerver.models import (
-    Realm,
-    RealmAuditLog,
-    RealmDomain,
-    RealmDomainDict,
-    UserProfile,
-    get_realm_domains,
-)
+from zerver.models import Realm, RealmAuditLog, RealmDomain, UserProfile
+from zerver.models.realms import RealmDomainDict, get_realm_domains
 from zerver.models.users import active_user_ids
 from zerver.tornado.django_api import send_event_on_commit
 
diff --git a/zerver/actions/realm_settings.py b/zerver/actions/realm_settings.py
index 4817bfae14..1005bda63c 100644
--- a/zerver/actions/realm_settings.py
+++ b/zerver/actions/realm_settings.py
@@ -33,9 +33,9 @@ from zerver.models import (
     Subscription,
     UserGroup,
     UserProfile,
-    get_realm,
 )
 from zerver.models.groups import SystemGroups
+from zerver.models.realms import get_realm
 from zerver.models.users import active_user_ids
 from zerver.tornado.django_api import send_event, send_event_on_commit
 
diff --git a/zerver/actions/users.py b/zerver/actions/users.py
index bda9c80aa9..8badc9f7b4 100644
--- a/zerver/actions/users.py
+++ b/zerver/actions/users.py
@@ -42,8 +42,8 @@ from zerver.models import (
     UserGroupMembership,
     UserProfile,
     get_bot_services,
-    get_fake_email_domain,
 )
+from zerver.models.realms import get_fake_email_domain
 from zerver.models.users import (
     active_non_guest_user_ids,
     active_user_ids,
diff --git a/zerver/context_processors.py b/zerver/context_processors.py
index 9ecf9fcf7f..b7d8df6565 100644
--- a/zerver/context_processors.py
+++ b/zerver/context_processors.py
@@ -20,7 +20,8 @@ from zerver.lib.realm_icon import get_realm_icon_url
 from zerver.lib.request import RequestNotes
 from zerver.lib.send_email import FromAddress
 from zerver.lib.subdomains import get_subdomain, is_root_domain_available
-from zerver.models import Realm, UserProfile, get_realm
+from zerver.models import Realm, UserProfile
+from zerver.models.realms import get_realm
 from zproject.backends import (
     AUTH_BACKEND_NAME_MAP,
     auth_enabled_helper,
diff --git a/zerver/forms.py b/zerver/forms.py
index ac53d952ef..fdf253787b 100644
--- a/zerver/forms.py
+++ b/zerver/forms.py
@@ -35,12 +35,11 @@ from zerver.lib.send_email import FromAddress, send_email
 from zerver.lib.soft_deactivation import queue_soft_reactivation
 from zerver.lib.subdomains import get_subdomain, is_root_domain_available
 from zerver.lib.users import check_full_name
-from zerver.models import (
+from zerver.models import Realm, UserProfile
+from zerver.models.realms import (
     DisposableEmailError,
     DomainNotAllowedForRealmError,
     EmailContainsPlusError,
-    Realm,
-    UserProfile,
     get_realm,
 )
 from zerver.models.users import get_user_by_delivery_email, is_cross_realm_bot_email
diff --git a/zerver/lib/cache.py b/zerver/lib/cache.py
index 6725ca9504..4f74a1a874 100644
--- a/zerver/lib/cache.py
+++ b/zerver/lib/cache.py
@@ -591,7 +591,7 @@ def flush_muting_users_cache(*, instance: "MutedUser", **kwargs: object) -> None
     cache_delete(get_muting_users_cache_key(mute_object.muted_user_id))
 
 
-# Called by models/__init__.py to flush various caches whenever we save
+# Called by models/realms.py to flush various caches whenever we save
 # a Realm object.  The main tricky thing here is that Realm info is
 # generally cached indirectly through user_profile objects.
 def flush_realm(
diff --git a/zerver/lib/create_user.py b/zerver/lib/create_user.py
index b5a969df62..cc4776dbd1 100644
--- a/zerver/lib/create_user.py
+++ b/zerver/lib/create_user.py
@@ -18,8 +18,8 @@ from zerver.models import (
     Subscription,
     UserBaseSettings,
     UserProfile,
-    get_fake_email_domain,
 )
+from zerver.models.realms import get_fake_email_domain
 
 
 def copy_default_settings(
diff --git a/zerver/lib/email_validation.py b/zerver/lib/email_validation.py
index be7416cdcf..b8d418863c 100644
--- a/zerver/lib/email_validation.py
+++ b/zerver/lib/email_validation.py
@@ -8,12 +8,11 @@ from django.utils.translation import gettext as _
 from zerver.lib.name_restrictions import is_disposable_domain
 
 # TODO: Move DisposableEmailError, etc. into here.
-from zerver.models import (
+from zerver.models import Realm, RealmDomain
+from zerver.models.realms import (
     DisposableEmailError,
     DomainNotAllowedForRealmError,
     EmailContainsPlusError,
-    Realm,
-    RealmDomain,
 )
 from zerver.models.users import get_users_by_delivery_email, is_cross_realm_bot_email
 
diff --git a/zerver/lib/events.py b/zerver/lib/events.py
index bd50e91064..9c60f83f88 100644
--- a/zerver/lib/events.py
+++ b/zerver/lib/events.py
@@ -82,11 +82,11 @@ from zerver.models import (
     custom_profile_fields_for_realm,
     get_all_custom_emoji_for_realm,
     get_default_stream_groups,
-    get_realm_domains,
     get_realm_playgrounds,
     linkifiers_for_realm,
 )
 from zerver.models.constants import MAX_TOPIC_NAME_LENGTH
+from zerver.models.realms import get_realm_domains
 from zerver.tornado.django_api import get_user_events, request_event_queue
 from zproject.backends import email_auth_enabled, password_auth_enabled
 
diff --git a/zerver/lib/export.py b/zerver/lib/export.py
index 46dffacf27..136e582f86 100644
--- a/zerver/lib/export.py
+++ b/zerver/lib/export.py
@@ -69,8 +69,8 @@ from zerver.models import (
     UserProfile,
     UserStatus,
     UserTopic,
-    get_realm,
 )
+from zerver.models.realms import get_realm
 from zerver.models.users import get_system_bot, get_user_profile_by_id
 
 # Custom mypy types follow:
diff --git a/zerver/lib/import_realm.py b/zerver/lib/import_realm.py
index c84299ae20..6347214856 100644
--- a/zerver/lib/import_realm.py
+++ b/zerver/lib/import_realm.py
@@ -77,9 +77,9 @@ from zerver.models import (
     UserStatus,
     UserTopic,
     get_huddle_hash,
-    get_realm,
 )
 from zerver.models.groups import SystemGroups
+from zerver.models.realms import get_realm
 from zerver.models.users import get_system_bot, get_user_profile_by_id
 
 realm_tables = [
diff --git a/zerver/lib/message.py b/zerver/lib/message.py
index 322c17d05c..f66fed5c66 100644
--- a/zerver/lib/message.py
+++ b/zerver/lib/message.py
@@ -75,11 +75,11 @@ from zerver.models import (
     UserProfile,
     UserTopic,
     get_display_recipient_by_id,
-    get_fake_email_domain,
     get_usermessage_by_message_id,
     query_for_ids,
 )
 from zerver.models.constants import MAX_TOPIC_NAME_LENGTH
+from zerver.models.realms import get_fake_email_domain
 
 
 class MessageDetailsDict(TypedDict, total=False):
diff --git a/zerver/lib/push_notifications.py b/zerver/lib/push_notifications.py
index dd66779fb7..3a51ff762a 100644
--- a/zerver/lib/push_notifications.py
+++ b/zerver/lib/push_notifications.py
@@ -65,8 +65,8 @@ from zerver.models import (
     UserMessage,
     UserProfile,
     get_display_recipient,
-    get_fake_email_domain,
 )
+from zerver.models.realms import get_fake_email_domain
 from zerver.models.users import get_user_profile_by_id
 
 if TYPE_CHECKING:
diff --git a/zerver/lib/remote_server.py b/zerver/lib/remote_server.py
index 1dc0fc6c3c..3d92b01493 100644
--- a/zerver/lib/remote_server.py
+++ b/zerver/lib/remote_server.py
@@ -22,7 +22,8 @@ from zerver.lib.exceptions import (
 )
 from zerver.lib.outgoing_http import OutgoingSession
 from zerver.lib.queue import queue_event_on_commit
-from zerver.models import OrgTypeEnum, Realm, RealmAuditLog
+from zerver.models import Realm, RealmAuditLog
+from zerver.models.realms import OrgTypeEnum
 
 
 class PushBouncerSession(OutgoingSession):
diff --git a/zerver/lib/scim.py b/zerver/lib/scim.py
index ceb0d80b48..24971c1bc8 100644
--- a/zerver/lib/scim.py
+++ b/zerver/lib/scim.py
@@ -15,11 +15,11 @@ from zerver.actions.users import do_change_user_role, do_deactivate_user
 from zerver.lib.email_validation import email_allowed_for_realm, validate_email_not_already_in_realm
 from zerver.lib.request import RequestNotes
 from zerver.lib.subdomains import get_subdomain
-from zerver.models import (
+from zerver.models import UserProfile
+from zerver.models.realms import (
     DisposableEmailError,
     DomainNotAllowedForRealmError,
     EmailContainsPlusError,
-    UserProfile,
 )
 
 
diff --git a/zerver/lib/test_classes.py b/zerver/lib/test_classes.py
index 7399a6db11..dc767291ef 100644
--- a/zerver/lib/test_classes.py
+++ b/zerver/lib/test_classes.py
@@ -107,12 +107,11 @@ from zerver.models import (
     UserMessage,
     UserProfile,
     UserStatus,
-    clear_supported_auth_backends_cache,
-    get_realm,
     get_realm_stream,
     get_stream,
 )
 from zerver.models.groups import SystemGroups
+from zerver.models.realms import clear_supported_auth_backends_cache, get_realm
 from zerver.models.users import get_system_bot, get_user, get_user_by_delivery_email
 from zerver.openapi.openapi import validate_against_openapi_schema, validate_request
 from zerver.tornado.event_queue import clear_client_event_queues_for_testing
diff --git a/zerver/lib/test_helpers.py b/zerver/lib/test_helpers.py
index e31576932d..ef5021e712 100644
--- a/zerver/lib/test_helpers.py
+++ b/zerver/lib/test_helpers.py
@@ -60,9 +60,9 @@ from zerver.models import (
     UserMessage,
     UserProfile,
     get_client,
-    get_realm,
     get_stream,
 )
+from zerver.models.realms import get_realm
 from zerver.tornado.handlers import AsyncDjangoHandler, allocate_handler_id
 from zilencer.models import RemoteZulipServer
 from zproject.backends import ExternalAuthDataDict, ExternalAuthResult
diff --git a/zerver/lib/users.py b/zerver/lib/users.py
index 6a26218300..b693d6502c 100644
--- a/zerver/lib/users.py
+++ b/zerver/lib/users.py
@@ -36,9 +36,9 @@ from zerver.models import (
     Subscription,
     UserMessage,
     UserProfile,
-    get_fake_email_domain,
 )
 from zerver.models.groups import SystemGroups
+from zerver.models.realms import get_fake_email_domain
 from zerver.models.users import (
     active_non_guest_user_ids,
     active_user_ids,
diff --git a/zerver/management/commands/realm_domain.py b/zerver/management/commands/realm_domain.py
index f8c70956e8..e33ab28711 100644
--- a/zerver/management/commands/realm_domain.py
+++ b/zerver/management/commands/realm_domain.py
@@ -9,7 +9,8 @@ from typing_extensions import override
 
 from zerver.lib.domains import validate_domain
 from zerver.lib.management import ZulipBaseCommand
-from zerver.models import RealmDomain, get_realm_domains
+from zerver.models import RealmDomain
+from zerver.models.realms import get_realm_domains
 
 
 class Command(ZulipBaseCommand):
diff --git a/zerver/management/commands/send_to_email_mirror.py b/zerver/management/commands/send_to_email_mirror.py
index 8674f07ce6..02c65368de 100644
--- a/zerver/management/commands/send_to_email_mirror.py
+++ b/zerver/management/commands/send_to_email_mirror.py
@@ -13,7 +13,8 @@ from typing_extensions import override
 from zerver.lib.email_mirror import mirror_email_message
 from zerver.lib.email_mirror_helpers import encode_email_address
 from zerver.lib.management import ZulipBaseCommand
-from zerver.models import Realm, get_realm, get_stream
+from zerver.models import Realm, get_stream
+from zerver.models.realms import get_realm
 
 # This command loads an email from a specified file and sends it
 # to the email mirror. Simple emails can be passed in a JSON file,
diff --git a/zerver/management/commands/send_webhook_fixture_message.py b/zerver/management/commands/send_webhook_fixture_message.py
index d88f04055f..3e6456d034 100644
--- a/zerver/management/commands/send_webhook_fixture_message.py
+++ b/zerver/management/commands/send_webhook_fixture_message.py
@@ -9,7 +9,7 @@ from typing_extensions import override
 
 from zerver.lib.management import ZulipBaseCommand
 from zerver.lib.webhooks.common import standardize_headers
-from zerver.models import get_realm
+from zerver.models.realms import get_realm
 
 
 class Command(ZulipBaseCommand):
diff --git a/zerver/middleware.py b/zerver/middleware.py
index cd1b3a9b29..5e4c7ecc78 100644
--- a/zerver/middleware.py
+++ b/zerver/middleware.py
@@ -42,7 +42,8 @@ from zerver.lib.response import (
 )
 from zerver.lib.subdomains import get_subdomain
 from zerver.lib.user_agent import parse_user_agent
-from zerver.models import Realm, get_realm
+from zerver.models import Realm
+from zerver.models.realms import get_realm
 
 ParamT = ParamSpec("ParamT")
 logger = logging.getLogger("zulip.requests")
diff --git a/zerver/migrations/0481_alter_realm_uuid_alter_realm_uuid_owner_secret.py b/zerver/migrations/0481_alter_realm_uuid_alter_realm_uuid_owner_secret.py
index c30da3f7db..bacf183d63 100644
--- a/zerver/migrations/0481_alter_realm_uuid_alter_realm_uuid_owner_secret.py
+++ b/zerver/migrations/0481_alter_realm_uuid_alter_realm_uuid_owner_secret.py
@@ -4,7 +4,7 @@ import uuid
 
 from django.db import migrations, models
 
-from zerver.models import generate_realm_uuid_owner_secret
+from zerver.models.realms import generate_realm_uuid_owner_secret
 
 
 class Migration(migrations.Migration):
diff --git a/zerver/models/__init__.py b/zerver/models/__init__.py
index 3d6497c230..69e2757bec 100644
--- a/zerver/models/__init__.py
+++ b/zerver/models/__init__.py
@@ -6,10 +6,7 @@ import secrets
 import time
 from collections import defaultdict
 from datetime import datetime, timedelta, timezone
-from email.headerregistry import Address
-from enum import Enum
 from typing import (
-    TYPE_CHECKING,
     Any,
     Callable,
     Dict,
@@ -22,9 +19,7 @@ from typing import (
     TypeVar,
     Union,
 )
-from uuid import uuid4
 
-import django.contrib.auth
 import orjson
 import re2
 import uri_template
@@ -37,12 +32,12 @@ from django.contrib.postgres.indexes import GinIndex
 from django.contrib.postgres.search import SearchVectorField
 from django.core.exceptions import ValidationError
 from django.core.serializers.json import DjangoJSONEncoder
-from django.core.validators import MinLengthValidator, RegexValidator, validate_email
+from django.core.validators import MinLengthValidator, RegexValidator
 from django.db import models, transaction
 from django.db.backends.base.base import BaseDatabaseWrapper
-from django.db.models import CASCADE, Exists, F, OuterRef, Q, QuerySet, Sum
+from django.db.models import CASCADE, Exists, F, OuterRef, Q, QuerySet
 from django.db.models.functions import Lower, Upper
-from django.db.models.signals import post_delete, post_save, pre_delete
+from django.db.models.signals import post_delete, post_save
 from django.db.models.sql.compiler import SQLCompiler
 from django.utils.timezone import now as timezone_now
 from django.utils.translation import gettext as _
@@ -58,20 +53,17 @@ from zerver.lib.cache import (
     cache_with_key,
     flush_message,
     flush_muting_users_cache,
-    flush_realm,
     flush_stream,
     flush_submessage,
     flush_used_upload_space_cache,
-    get_realm_used_upload_space_cache_key,
     realm_alert_words_automaton_cache_key,
     realm_alert_words_cache_key,
 )
-from zerver.lib.exceptions import JsonableError, RateLimitedError
+from zerver.lib.exceptions import RateLimitedError
 from zerver.lib.per_request_cache import (
     flush_per_request_cache,
     return_same_value_during_entire_request,
 )
-from zerver.lib.pysa import mark_sanitized
 from zerver.lib.timestamp import datetime_to_timestamp
 from zerver.lib.types import (
     DefaultStreamDict,
@@ -89,7 +81,6 @@ from zerver.lib.types import (
     UserFieldElement,
     Validator,
 )
-from zerver.lib.utils import generate_api_key
 from zerver.lib.validator import (
     check_date,
     check_int,
@@ -104,17 +95,14 @@ from zerver.models.groups import GroupGroupMembership as GroupGroupMembership
 from zerver.models.groups import SystemGroups
 from zerver.models.groups import UserGroup as UserGroup
 from zerver.models.groups import UserGroupMembership as UserGroupMembership
+from zerver.models.realms import Realm as Realm
+from zerver.models.realms import RealmAuthenticationMethod as RealmAuthenticationMethod
+from zerver.models.realms import RealmDomain as RealmDomain
 from zerver.models.users import RealmUserDefault as RealmUserDefault
 from zerver.models.users import UserBaseSettings as UserBaseSettings
 from zerver.models.users import UserProfile as UserProfile
 from zerver.models.users import get_user_profile_by_id_in_realm
 
-SECONDS_PER_DAY = 86400
-
-if TYPE_CHECKING:
-    # We use ModelBackend only for typing. Importing it otherwise causes circular dependency.
-    from django.contrib.auth.backends import ModelBackend
-
 
 class EmojiInfo(TypedDict):
     id: str
@@ -227,967 +215,6 @@ def get_all_custom_emoji_for_realm_cache_key(realm_id: int) -> str:
     return f"realm_emoji:{realm_id}"
 
 
-# This simple call-once caching saves ~500us in auth_enabled_helper,
-# which is a significant optimization for common_context.  Note that
-# these values cannot change in a running production system, but do
-# regularly change within unit tests; we address the latter by calling
-# clear_supported_auth_backends_cache in our standard tearDown code.
-supported_backends: Optional[List["ModelBackend"]] = None
-
-
-def supported_auth_backends() -> List["ModelBackend"]:
-    global supported_backends
-    # Caching temporarily disabled for debugging
-    supported_backends = django.contrib.auth.get_backends()
-    assert supported_backends is not None
-    return supported_backends
-
-
-def clear_supported_auth_backends_cache() -> None:
-    global supported_backends
-    supported_backends = None
-
-
-class RealmAuthenticationMethod(models.Model):
-    """
-    Tracks which authentication backends are enabled for a realm.
-    An enabled backend is represented in this table a row with appropriate
-    .realm value and .name matching the name of the target backend in the
-    AUTH_BACKEND_NAME_MAP dict.
-    """
-
-    realm = models.ForeignKey("Realm", on_delete=CASCADE, db_index=True)
-    name = models.CharField(max_length=80)
-
-    class Meta:
-        unique_together = ("realm", "name")
-
-
-def generate_realm_uuid_owner_secret() -> str:
-    token = generate_api_key()
-
-    # We include a prefix to facilitate scanning for accidental
-    # disclosure of secrets e.g. in Github commit pushes.
-    return f"zuliprealm_{token}"
-
-
-class OrgTypeEnum(Enum):
-    Unspecified = 0
-    Business = 10
-    OpenSource = 20
-    EducationNonProfit = 30
-    Education = 35
-    Research = 40
-    Event = 50
-    NonProfit = 60
-    Government = 70
-    PoliticalGroup = 80
-    Community = 90
-    Personal = 100
-    Other = 1000
-
-
-class OrgTypeDict(TypedDict):
-    name: str
-    id: int
-    hidden: bool
-    display_order: int
-    onboarding_zulip_guide_url: Optional[str]
-
-
-class Realm(models.Model):  # type: ignore[django-manager-missing] # django-stubs cannot resolve the custom CTEManager yet https://github.com/typeddjango/django-stubs/issues/1023
-    MAX_REALM_NAME_LENGTH = 40
-    MAX_REALM_DESCRIPTION_LENGTH = 1000
-    MAX_REALM_SUBDOMAIN_LENGTH = 40
-    MAX_REALM_REDIRECT_URL_LENGTH = 128
-
-    INVITES_STANDARD_REALM_DAILY_MAX = 3000
-    MESSAGE_VISIBILITY_LIMITED = 10000
-    SUBDOMAIN_FOR_ROOT_DOMAIN = ""
-    WILDCARD_MENTION_THRESHOLD = 15
-
-    # User-visible display name and description used on e.g. the organization homepage
-    name = models.CharField(max_length=MAX_REALM_NAME_LENGTH)
-    description = models.TextField(default="")
-
-    # A short, identifier-like name for the organization.  Used in subdomains;
-    # e.g. on a server at example.com, an org with string_id `foo` is reached
-    # at `foo.example.com`.
-    string_id = models.CharField(max_length=MAX_REALM_SUBDOMAIN_LENGTH, unique=True)
-
-    # uuid and a secret for the sake of per-realm authentication with the push notification
-    # bouncer.
-    uuid = models.UUIDField(default=uuid4, unique=True)
-    uuid_owner_secret = models.TextField(default=generate_realm_uuid_owner_secret)
-    # Whether push notifications are working for this realm, and
-    # whether there is a specific date at which we expect that to
-    # cease to be the case.
-    push_notifications_enabled = models.BooleanField(default=False, db_index=True)
-    push_notifications_enabled_end_timestamp = models.DateTimeField(default=None, null=True)
-
-    date_created = models.DateTimeField(default=timezone_now)
-    demo_organization_scheduled_deletion_date = models.DateTimeField(default=None, null=True)
-    deactivated = models.BooleanField(default=False)
-
-    # Redirect URL if the Realm has moved to another server
-    deactivated_redirect = models.URLField(max_length=MAX_REALM_REDIRECT_URL_LENGTH, null=True)
-
-    # See RealmDomain for the domains that apply for a given organization.
-    emails_restricted_to_domains = models.BooleanField(default=False)
-
-    invite_required = models.BooleanField(default=True)
-
-    _max_invites = models.IntegerField(null=True, db_column="max_invites")
-    disallow_disposable_email_addresses = models.BooleanField(default=True)
-
-    # Allow users to access web-public streams without login. This
-    # setting also controls API access of web-public streams.
-    enable_spectator_access = models.BooleanField(default=False)
-
-    # Whether organization has given permission to be advertised in the
-    # Zulip communities directory.
-    want_advertise_in_communities_directory = models.BooleanField(default=False, db_index=True)
-
-    # Whether the organization has enabled inline image and URL previews.
-    inline_image_preview = models.BooleanField(default=True)
-    inline_url_embed_preview = models.BooleanField(default=False)
-
-    # Whether digest emails are enabled for the organization.
-    digest_emails_enabled = models.BooleanField(default=False)
-    # Day of the week on which the digest is sent (default: Tuesday).
-    digest_weekday = models.SmallIntegerField(default=1)
-
-    send_welcome_emails = models.BooleanField(default=True)
-    message_content_allowed_in_email_notifications = models.BooleanField(default=True)
-
-    mandatory_topics = models.BooleanField(default=False)
-
-    name_changes_disabled = models.BooleanField(default=False)
-    email_changes_disabled = models.BooleanField(default=False)
-    avatar_changes_disabled = models.BooleanField(default=False)
-
-    POLICY_MEMBERS_ONLY = 1
-    POLICY_ADMINS_ONLY = 2
-    POLICY_FULL_MEMBERS_ONLY = 3
-    POLICY_MODERATORS_ONLY = 4
-    POLICY_EVERYONE = 5
-    POLICY_NOBODY = 6
-    POLICY_OWNERS_ONLY = 7
-
-    COMMON_POLICY_TYPES = [
-        POLICY_MEMBERS_ONLY,
-        POLICY_ADMINS_ONLY,
-        POLICY_FULL_MEMBERS_ONLY,
-        POLICY_MODERATORS_ONLY,
-    ]
-
-    COMMON_MESSAGE_POLICY_TYPES = [
-        POLICY_MEMBERS_ONLY,
-        POLICY_ADMINS_ONLY,
-        POLICY_FULL_MEMBERS_ONLY,
-        POLICY_MODERATORS_ONLY,
-        POLICY_EVERYONE,
-    ]
-
-    INVITE_TO_REALM_POLICY_TYPES = [
-        POLICY_MEMBERS_ONLY,
-        POLICY_ADMINS_ONLY,
-        POLICY_FULL_MEMBERS_ONLY,
-        POLICY_MODERATORS_ONLY,
-        POLICY_NOBODY,
-    ]
-
-    # We don't allow granting roles less than Moderator access to
-    # create web-public streams, since it's a sensitive feature that
-    # can be used to send spam.
-    CREATE_WEB_PUBLIC_STREAM_POLICY_TYPES = [
-        POLICY_ADMINS_ONLY,
-        POLICY_MODERATORS_ONLY,
-        POLICY_OWNERS_ONLY,
-        POLICY_NOBODY,
-    ]
-
-    EDIT_TOPIC_POLICY_TYPES = [
-        POLICY_MEMBERS_ONLY,
-        POLICY_ADMINS_ONLY,
-        POLICY_FULL_MEMBERS_ONLY,
-        POLICY_MODERATORS_ONLY,
-        POLICY_EVERYONE,
-        POLICY_NOBODY,
-    ]
-
-    MOVE_MESSAGES_BETWEEN_STREAMS_POLICY_TYPES = INVITE_TO_REALM_POLICY_TYPES
-
-    DEFAULT_MOVE_MESSAGE_LIMIT_SECONDS = 7 * SECONDS_PER_DAY
-
-    move_messages_within_stream_limit_seconds = models.PositiveIntegerField(
-        default=DEFAULT_MOVE_MESSAGE_LIMIT_SECONDS, null=True
-    )
-
-    move_messages_between_streams_limit_seconds = models.PositiveIntegerField(
-        default=DEFAULT_MOVE_MESSAGE_LIMIT_SECONDS, null=True
-    )
-
-    # Who in the organization is allowed to add custom emojis.
-    add_custom_emoji_policy = models.PositiveSmallIntegerField(default=POLICY_MEMBERS_ONLY)
-
-    # Who in the organization is allowed to create streams.
-    create_public_stream_policy = models.PositiveSmallIntegerField(default=POLICY_MEMBERS_ONLY)
-    create_private_stream_policy = models.PositiveSmallIntegerField(default=POLICY_MEMBERS_ONLY)
-    create_web_public_stream_policy = models.PositiveSmallIntegerField(default=POLICY_OWNERS_ONLY)
-
-    # Who in the organization is allowed to delete messages they themselves sent.
-    delete_own_message_policy = models.PositiveSmallIntegerField(default=POLICY_ADMINS_ONLY)
-
-    # Who in the organization is allowed to edit topics of any message.
-    edit_topic_policy = models.PositiveSmallIntegerField(default=POLICY_EVERYONE)
-
-    # Who in the organization is allowed to invite other users to organization.
-    invite_to_realm_policy = models.PositiveSmallIntegerField(default=POLICY_MEMBERS_ONLY)
-
-    # UserGroup whose members are allowed to create invite link.
-    create_multiuse_invite_group = models.ForeignKey(
-        "UserGroup", on_delete=models.RESTRICT, related_name="+"
-    )
-
-    # on_delete field here is set to RESTRICT because we don't want to allow
-    # deleting a user group in case it is referenced by this setting.
-    # We are not using PROTECT since we want to allow deletion of user groups
-    # when realm itself is deleted.
-    can_access_all_users_group = models.ForeignKey(
-        "UserGroup", on_delete=models.RESTRICT, related_name="+"
-    )
-
-    # Who in the organization is allowed to invite other users to streams.
-    invite_to_stream_policy = models.PositiveSmallIntegerField(default=POLICY_MEMBERS_ONLY)
-
-    # Who in the organization is allowed to move messages between streams.
-    move_messages_between_streams_policy = models.PositiveSmallIntegerField(
-        default=POLICY_ADMINS_ONLY
-    )
-
-    user_group_edit_policy = models.PositiveSmallIntegerField(default=POLICY_MEMBERS_ONLY)
-
-    PRIVATE_MESSAGE_POLICY_UNLIMITED = 1
-    PRIVATE_MESSAGE_POLICY_DISABLED = 2
-    private_message_policy = models.PositiveSmallIntegerField(
-        default=PRIVATE_MESSAGE_POLICY_UNLIMITED
-    )
-    PRIVATE_MESSAGE_POLICY_TYPES = [
-        PRIVATE_MESSAGE_POLICY_UNLIMITED,
-        PRIVATE_MESSAGE_POLICY_DISABLED,
-    ]
-
-    # Global policy for who is allowed to use wildcard mentions in
-    # streams with a large number of subscribers.  Anyone can use
-    # wildcard mentions in small streams regardless of this setting.
-    WILDCARD_MENTION_POLICY_EVERYONE = 1
-    WILDCARD_MENTION_POLICY_MEMBERS = 2
-    WILDCARD_MENTION_POLICY_FULL_MEMBERS = 3
-    WILDCARD_MENTION_POLICY_ADMINS = 5
-    WILDCARD_MENTION_POLICY_NOBODY = 6
-    WILDCARD_MENTION_POLICY_MODERATORS = 7
-    wildcard_mention_policy = models.PositiveSmallIntegerField(
-        default=WILDCARD_MENTION_POLICY_ADMINS,
-    )
-    WILDCARD_MENTION_POLICY_TYPES = [
-        WILDCARD_MENTION_POLICY_EVERYONE,
-        WILDCARD_MENTION_POLICY_MEMBERS,
-        WILDCARD_MENTION_POLICY_FULL_MEMBERS,
-        WILDCARD_MENTION_POLICY_ADMINS,
-        WILDCARD_MENTION_POLICY_NOBODY,
-        WILDCARD_MENTION_POLICY_MODERATORS,
-    ]
-
-    # Threshold in days for new users to create streams, and potentially take
-    # some other actions.
-    waiting_period_threshold = models.PositiveIntegerField(default=0)
-
-    DEFAULT_MESSAGE_CONTENT_DELETE_LIMIT_SECONDS = (
-        600  # if changed, also change in admin.js, setting_org.js
-    )
-    MESSAGE_TIME_LIMIT_SETTING_SPECIAL_VALUES_MAP = {
-        "unlimited": None,
-    }
-    message_content_delete_limit_seconds = models.PositiveIntegerField(
-        default=DEFAULT_MESSAGE_CONTENT_DELETE_LIMIT_SECONDS, null=True
-    )
-
-    allow_message_editing = models.BooleanField(default=True)
-    DEFAULT_MESSAGE_CONTENT_EDIT_LIMIT_SECONDS = (
-        600  # if changed, also change in admin.js, setting_org.js
-    )
-    message_content_edit_limit_seconds = models.PositiveIntegerField(
-        default=DEFAULT_MESSAGE_CONTENT_EDIT_LIMIT_SECONDS, null=True
-    )
-
-    # Whether users have access to message edit history
-    allow_edit_history = models.BooleanField(default=True)
-
-    # Defaults for new users
-    default_language = models.CharField(default="en", max_length=MAX_LANGUAGE_ID_LENGTH)
-
-    DEFAULT_NOTIFICATION_STREAM_NAME = "general"
-    INITIAL_PRIVATE_STREAM_NAME = "core team"
-    STREAM_EVENTS_NOTIFICATION_TOPIC = gettext_lazy("stream events")
-    notifications_stream = models.ForeignKey(
-        "Stream",
-        related_name="+",
-        null=True,
-        blank=True,
-        on_delete=models.SET_NULL,
-    )
-    signup_notifications_stream = models.ForeignKey(
-        "Stream",
-        related_name="+",
-        null=True,
-        blank=True,
-        on_delete=models.SET_NULL,
-    )
-
-    MESSAGE_RETENTION_SPECIAL_VALUES_MAP = {
-        "unlimited": -1,
-    }
-    # For old messages being automatically deleted
-    message_retention_days = models.IntegerField(null=False, default=-1)
-
-    # When non-null, all but the latest this many messages in the organization
-    # are inaccessible to users (but not deleted).
-    message_visibility_limit = models.IntegerField(null=True)
-
-    # Messages older than this message ID in the organization are inaccessible.
-    first_visible_message_id = models.IntegerField(default=0)
-
-    # Valid org types
-    ORG_TYPES: Dict[str, OrgTypeDict] = {
-        "unspecified": {
-            "name": "Unspecified",
-            "id": OrgTypeEnum.Unspecified.value,
-            "hidden": True,
-            "display_order": 0,
-            "onboarding_zulip_guide_url": None,
-        },
-        "business": {
-            "name": "Business",
-            "id": OrgTypeEnum.Business.value,
-            "hidden": False,
-            "display_order": 1,
-            "onboarding_zulip_guide_url": "https://zulip.com/for/business/",
-        },
-        "opensource": {
-            "name": "Open-source project",
-            "id": OrgTypeEnum.OpenSource.value,
-            "hidden": False,
-            "display_order": 2,
-            "onboarding_zulip_guide_url": "https://zulip.com/for/open-source/",
-        },
-        "education_nonprofit": {
-            "name": "Education (non-profit)",
-            "id": OrgTypeEnum.EducationNonProfit.value,
-            "hidden": False,
-            "display_order": 3,
-            "onboarding_zulip_guide_url": "https://zulip.com/for/education/",
-        },
-        "education": {
-            "name": "Education (for-profit)",
-            "id": OrgTypeEnum.Education.value,
-            "hidden": False,
-            "display_order": 4,
-            "onboarding_zulip_guide_url": "https://zulip.com/for/education/",
-        },
-        "research": {
-            "name": "Research",
-            "id": OrgTypeEnum.Research.value,
-            "hidden": False,
-            "display_order": 5,
-            "onboarding_zulip_guide_url": "https://zulip.com/for/research/",
-        },
-        "event": {
-            "name": "Event or conference",
-            "id": OrgTypeEnum.Event.value,
-            "hidden": False,
-            "display_order": 6,
-            "onboarding_zulip_guide_url": "https://zulip.com/for/events/",
-        },
-        "nonprofit": {
-            "name": "Non-profit (registered)",
-            "id": OrgTypeEnum.NonProfit.value,
-            "hidden": False,
-            "display_order": 7,
-            "onboarding_zulip_guide_url": "https://zulip.com/for/communities/",
-        },
-        "government": {
-            "name": "Government",
-            "id": OrgTypeEnum.Government.value,
-            "hidden": False,
-            "display_order": 8,
-            "onboarding_zulip_guide_url": None,
-        },
-        "political_group": {
-            "name": "Political group",
-            "id": OrgTypeEnum.PoliticalGroup.value,
-            "hidden": False,
-            "display_order": 9,
-            "onboarding_zulip_guide_url": None,
-        },
-        "community": {
-            "name": "Community",
-            "id": OrgTypeEnum.Community.value,
-            "hidden": False,
-            "display_order": 10,
-            "onboarding_zulip_guide_url": "https://zulip.com/for/communities/",
-        },
-        "personal": {
-            "name": "Personal",
-            "id": OrgTypeEnum.Personal.value,
-            "hidden": False,
-            "display_order": 100,
-            "onboarding_zulip_guide_url": None,
-        },
-        "other": {
-            "name": "Other",
-            "id": OrgTypeEnum.Other.value,
-            "hidden": False,
-            "display_order": 1000,
-            "onboarding_zulip_guide_url": None,
-        },
-    }
-
-    ORG_TYPE_IDS: List[int] = [t["id"] for t in ORG_TYPES.values()]
-
-    org_type = models.PositiveSmallIntegerField(
-        default=ORG_TYPES["unspecified"]["id"],
-        choices=[(t["id"], t["name"]) for t in ORG_TYPES.values()],
-    )
-
-    UPGRADE_TEXT_STANDARD = gettext_lazy("Available on Zulip Cloud Standard. Upgrade to access.")
-    UPGRADE_TEXT_PLUS = gettext_lazy("Available on Zulip Cloud Plus. Upgrade to access.")
-    # plan_type controls various features around resource/feature
-    # limitations for a Zulip organization on multi-tenant installations
-    # like Zulip Cloud.
-    PLAN_TYPE_SELF_HOSTED = 1
-    PLAN_TYPE_LIMITED = 2
-    PLAN_TYPE_STANDARD = 3
-    PLAN_TYPE_STANDARD_FREE = 4
-    PLAN_TYPE_PLUS = 10
-
-    # Used for creating realms with different plan types.
-    ALL_PLAN_TYPES = {
-        PLAN_TYPE_SELF_HOSTED: "self-hosted-plan",
-        PLAN_TYPE_LIMITED: "limited-plan",
-        PLAN_TYPE_STANDARD: "standard-plan",
-        PLAN_TYPE_STANDARD_FREE: "standard-free-plan",
-        PLAN_TYPE_PLUS: "plus-plan",
-    }
-    plan_type = models.PositiveSmallIntegerField(default=PLAN_TYPE_SELF_HOSTED)
-
-    # This value is also being used in web/src/settings_bots.bot_creation_policy_values.
-    # On updating it here, update it there as well.
-    BOT_CREATION_EVERYONE = 1
-    BOT_CREATION_LIMIT_GENERIC_BOTS = 2
-    BOT_CREATION_ADMINS_ONLY = 3
-    bot_creation_policy = models.PositiveSmallIntegerField(default=BOT_CREATION_EVERYONE)
-    BOT_CREATION_POLICY_TYPES = [
-        BOT_CREATION_EVERYONE,
-        BOT_CREATION_LIMIT_GENERIC_BOTS,
-        BOT_CREATION_ADMINS_ONLY,
-    ]
-
-    # See upload_quota_bytes; don't interpret upload_quota_gb directly.
-    UPLOAD_QUOTA_LIMITED = 5
-    UPLOAD_QUOTA_STANDARD = 50
-    upload_quota_gb = models.IntegerField(null=True)
-
-    VIDEO_CHAT_PROVIDERS = {
-        "disabled": {
-            "name": "None",
-            "id": 0,
-        },
-        "jitsi_meet": {
-            "name": "Jitsi Meet",
-            "id": 1,
-        },
-        # ID 2 was used for the now-deleted Google Hangouts.
-        # ID 3 reserved for optional Zoom, see below.
-        # ID 4 reserved for optional BigBlueButton, see below.
-    }
-
-    if settings.VIDEO_ZOOM_CLIENT_ID is not None and settings.VIDEO_ZOOM_CLIENT_SECRET is not None:
-        VIDEO_CHAT_PROVIDERS["zoom"] = {
-            "name": "Zoom",
-            "id": 3,
-        }
-
-    if settings.BIG_BLUE_BUTTON_SECRET is not None and settings.BIG_BLUE_BUTTON_URL is not None:
-        VIDEO_CHAT_PROVIDERS["big_blue_button"] = {"name": "BigBlueButton", "id": 4}
-
-    video_chat_provider = models.PositiveSmallIntegerField(
-        default=VIDEO_CHAT_PROVIDERS["jitsi_meet"]["id"]
-    )
-
-    JITSI_SERVER_SPECIAL_VALUES_MAP = {"default": None}
-    jitsi_server_url = models.URLField(null=True, default=None)
-
-    # Please access this via get_giphy_rating_options.
-    GIPHY_RATING_OPTIONS = {
-        "disabled": {
-            "name": gettext_lazy("GIPHY integration disabled"),
-            "id": 0,
-        },
-        # Source: https://github.com/Giphy/giphy-js/blob/master/packages/fetch-api/README.md#shared-options
-        "y": {
-            "name": gettext_lazy("Allow GIFs rated Y (Very young audience)"),
-            "id": 1,
-        },
-        "g": {
-            "name": gettext_lazy("Allow GIFs rated G (General audience)"),
-            "id": 2,
-        },
-        "pg": {
-            "name": gettext_lazy("Allow GIFs rated PG (Parental guidance)"),
-            "id": 3,
-        },
-        "pg-13": {
-            "name": gettext_lazy("Allow GIFs rated PG-13 (Parental guidance - under 13)"),
-            "id": 4,
-        },
-        "r": {
-            "name": gettext_lazy("Allow GIFs rated R (Restricted)"),
-            "id": 5,
-        },
-    }
-
-    # maximum rating of the GIFs that will be retrieved from GIPHY
-    giphy_rating = models.PositiveSmallIntegerField(default=GIPHY_RATING_OPTIONS["g"]["id"])
-
-    default_code_block_language = models.TextField(default="")
-
-    # Whether read receipts are enabled in the organization. If disabled,
-    # they will not be available regardless of users' personal settings.
-    enable_read_receipts = models.BooleanField(default=False)
-
-    # Whether clients should display "(guest)" after names of guest users.
-    enable_guest_user_indicator = models.BooleanField(default=True)
-
-    # Define the types of the various automatically managed properties
-    property_types: Dict[str, Union[type, Tuple[type, ...]]] = dict(
-        add_custom_emoji_policy=int,
-        allow_edit_history=bool,
-        allow_message_editing=bool,
-        avatar_changes_disabled=bool,
-        bot_creation_policy=int,
-        create_private_stream_policy=int,
-        create_public_stream_policy=int,
-        create_web_public_stream_policy=int,
-        default_code_block_language=str,
-        default_language=str,
-        delete_own_message_policy=int,
-        description=str,
-        digest_emails_enabled=bool,
-        digest_weekday=int,
-        disallow_disposable_email_addresses=bool,
-        edit_topic_policy=int,
-        email_changes_disabled=bool,
-        emails_restricted_to_domains=bool,
-        enable_guest_user_indicator=bool,
-        enable_read_receipts=bool,
-        enable_spectator_access=bool,
-        giphy_rating=int,
-        inline_image_preview=bool,
-        inline_url_embed_preview=bool,
-        invite_required=bool,
-        invite_to_realm_policy=int,
-        invite_to_stream_policy=int,
-        jitsi_server_url=(str, type(None)),
-        mandatory_topics=bool,
-        message_content_allowed_in_email_notifications=bool,
-        message_content_edit_limit_seconds=(int, type(None)),
-        message_content_delete_limit_seconds=(int, type(None)),
-        move_messages_between_streams_limit_seconds=(int, type(None)),
-        move_messages_within_stream_limit_seconds=(int, type(None)),
-        message_retention_days=(int, type(None)),
-        move_messages_between_streams_policy=int,
-        name=str,
-        name_changes_disabled=bool,
-        private_message_policy=int,
-        push_notifications_enabled=bool,
-        send_welcome_emails=bool,
-        user_group_edit_policy=int,
-        video_chat_provider=int,
-        waiting_period_threshold=int,
-        want_advertise_in_communities_directory=bool,
-        wildcard_mention_policy=int,
-    )
-
-    REALM_PERMISSION_GROUP_SETTINGS: Dict[str, GroupPermissionSetting] = dict(
-        create_multiuse_invite_group=GroupPermissionSetting(
-            require_system_group=True,
-            allow_internet_group=False,
-            allow_owners_group=False,
-            allow_nobody_group=True,
-            allow_everyone_group=False,
-            default_group_name=SystemGroups.ADMINISTRATORS,
-            id_field_name="create_multiuse_invite_group_id",
-        ),
-        can_access_all_users_group=GroupPermissionSetting(
-            require_system_group=True,
-            allow_internet_group=False,
-            allow_owners_group=False,
-            allow_nobody_group=False,
-            allow_everyone_group=True,
-            default_group_name=SystemGroups.EVERYONE,
-            id_field_name="can_access_all_users_group_id",
-            allowed_system_groups=[SystemGroups.EVERYONE, SystemGroups.MEMBERS],
-        ),
-    )
-
-    DIGEST_WEEKDAY_VALUES = [0, 1, 2, 3, 4, 5, 6]
-
-    # Icon is the square mobile icon.
-    ICON_FROM_GRAVATAR = "G"
-    ICON_UPLOADED = "U"
-    ICON_SOURCES = (
-        (ICON_FROM_GRAVATAR, "Hosted by Gravatar"),
-        (ICON_UPLOADED, "Uploaded by administrator"),
-    )
-    icon_source = models.CharField(
-        default=ICON_FROM_GRAVATAR,
-        choices=ICON_SOURCES,
-        max_length=1,
-    )
-    icon_version = models.PositiveSmallIntegerField(default=1)
-
-    # Logo is the horizontal logo we show in top-left of web app navbar UI.
-    LOGO_DEFAULT = "D"
-    LOGO_UPLOADED = "U"
-    LOGO_SOURCES = (
-        (LOGO_DEFAULT, "Default to Zulip"),
-        (LOGO_UPLOADED, "Uploaded by administrator"),
-    )
-    logo_source = models.CharField(
-        default=LOGO_DEFAULT,
-        choices=LOGO_SOURCES,
-        max_length=1,
-    )
-    logo_version = models.PositiveSmallIntegerField(default=1)
-
-    night_logo_source = models.CharField(
-        default=LOGO_DEFAULT,
-        choices=LOGO_SOURCES,
-        max_length=1,
-    )
-    night_logo_version = models.PositiveSmallIntegerField(default=1)
-
-    @override
-    def __str__(self) -> str:
-        return f"{self.string_id} {self.id}"
-
-    def get_giphy_rating_options(self) -> Dict[str, Dict[str, object]]:
-        """Wrapper function for GIPHY_RATING_OPTIONS that ensures evaluation
-        of the lazily evaluated `name` field without modifying the original."""
-        return {
-            rating_type: {"name": str(rating["name"]), "id": rating["id"]}
-            for rating_type, rating in self.GIPHY_RATING_OPTIONS.items()
-        }
-
-    def authentication_methods_dict(self) -> Dict[str, bool]:
-        """Returns the mapping from authentication flags to their status,
-        showing only those authentication flags that are supported on
-        the current server (i.e. if EmailAuthBackend is not configured
-        on the server, this will not return an entry for "Email")."""
-        # This mapping needs to be imported from here due to the cyclic
-        # dependency.
-        from zproject.backends import AUTH_BACKEND_NAME_MAP, all_implemented_backend_names
-
-        ret: Dict[str, bool] = {}
-        supported_backends = [type(backend) for backend in supported_auth_backends()]
-
-        for backend_name in all_implemented_backend_names():
-            backend_class = AUTH_BACKEND_NAME_MAP[backend_name]
-            if backend_class in supported_backends:
-                ret[backend_name] = False
-        for realm_authentication_method in RealmAuthenticationMethod.objects.filter(
-            realm_id=self.id
-        ):
-            backend_class = AUTH_BACKEND_NAME_MAP[realm_authentication_method.name]
-            if backend_class in supported_backends:
-                ret[realm_authentication_method.name] = True
-        return ret
-
-    def get_admin_users_and_bots(
-        self, include_realm_owners: bool = True
-    ) -> QuerySet["UserProfile"]:
-        """Use this in contexts where we want administrative users as well as
-        bots with administrator privileges, like send_event calls for
-        notifications to all administrator users.
-        """
-        if include_realm_owners:
-            roles = [UserProfile.ROLE_REALM_ADMINISTRATOR, UserProfile.ROLE_REALM_OWNER]
-        else:
-            roles = [UserProfile.ROLE_REALM_ADMINISTRATOR]
-
-        return UserProfile.objects.filter(
-            realm=self,
-            is_active=True,
-            role__in=roles,
-        )
-
-    def get_human_admin_users(self, include_realm_owners: bool = True) -> QuerySet["UserProfile"]:
-        """Use this in contexts where we want only human users with
-        administrative privileges, like sending an email to all of a
-        realm's administrators (bots don't have real email addresses).
-        """
-        if include_realm_owners:
-            roles = [UserProfile.ROLE_REALM_ADMINISTRATOR, UserProfile.ROLE_REALM_OWNER]
-        else:
-            roles = [UserProfile.ROLE_REALM_ADMINISTRATOR]
-
-        return UserProfile.objects.filter(
-            realm=self,
-            is_bot=False,
-            is_active=True,
-            role__in=roles,
-        )
-
-    def get_human_billing_admin_and_realm_owner_users(self) -> QuerySet["UserProfile"]:
-        return UserProfile.objects.filter(
-            Q(role=UserProfile.ROLE_REALM_OWNER) | Q(is_billing_admin=True),
-            realm=self,
-            is_bot=False,
-            is_active=True,
-        )
-
-    def get_active_users(self) -> QuerySet["UserProfile"]:
-        return UserProfile.objects.filter(realm=self, is_active=True)
-
-    def get_first_human_user(self) -> Optional["UserProfile"]:
-        """A useful value for communications with newly created realms.
-        Has a few fundamental limitations:
-
-        * Its value will be effectively random for realms imported from Slack or
-          other third-party tools.
-        * The user may be deactivated, etc., so it's not something that's useful
-          for features, permissions, etc.
-        """
-        return UserProfile.objects.filter(realm=self, is_bot=False).order_by("id").first()
-
-    def get_human_owner_users(self) -> QuerySet["UserProfile"]:
-        return UserProfile.objects.filter(
-            realm=self, is_bot=False, role=UserProfile.ROLE_REALM_OWNER, is_active=True
-        )
-
-    def get_bot_domain(self) -> str:
-        return get_fake_email_domain(self.host)
-
-    def get_notifications_stream(self) -> Optional["Stream"]:
-        if self.notifications_stream is not None and not self.notifications_stream.deactivated:
-            return self.notifications_stream
-        return None
-
-    def get_signup_notifications_stream(self) -> Optional["Stream"]:
-        if (
-            self.signup_notifications_stream is not None
-            and not self.signup_notifications_stream.deactivated
-        ):
-            return self.signup_notifications_stream
-        return None
-
-    @property
-    def max_invites(self) -> int:
-        if self._max_invites is None:
-            return settings.INVITES_DEFAULT_REALM_DAILY_MAX
-        return self._max_invites
-
-    @max_invites.setter
-    def max_invites(self, value: Optional[int]) -> None:
-        self._max_invites = value
-
-    def upload_quota_bytes(self) -> Optional[int]:
-        if self.upload_quota_gb is None:
-            return None
-        # We describe the quota to users in "GB" or "gigabytes", but actually apply
-        # it as gibibytes (GiB) to be a bit more generous in case of confusion.
-        return self.upload_quota_gb << 30
-
-    # `realm` instead of `self` here to make sure the parameters of the cache key
-    # function matches the original method.
-    @cache_with_key(
-        lambda realm: get_realm_used_upload_space_cache_key(realm.id), timeout=3600 * 24 * 7
-    )
-    def currently_used_upload_space_bytes(realm) -> int:  # noqa: N805
-        used_space = Attachment.objects.filter(realm=realm).aggregate(Sum("size"))["size__sum"]
-        if used_space is None:
-            return 0
-        return used_space
-
-    def ensure_not_on_limited_plan(self) -> None:
-        if self.plan_type == Realm.PLAN_TYPE_LIMITED:
-            raise JsonableError(str(self.UPGRADE_TEXT_STANDARD))
-
-    def can_enable_restricted_user_access_for_guests(self) -> None:
-        if self.plan_type not in [Realm.PLAN_TYPE_PLUS, Realm.PLAN_TYPE_SELF_HOSTED]:
-            raise JsonableError(str(self.UPGRADE_TEXT_PLUS))
-
-    @property
-    def subdomain(self) -> str:
-        return self.string_id
-
-    @property
-    def display_subdomain(self) -> str:
-        """Likely to be temporary function to avoid signup messages being sent
-        to an empty topic"""
-        if self.string_id == "":
-            return "."
-        return self.string_id
-
-    @property
-    def uri(self) -> str:
-        return settings.EXTERNAL_URI_SCHEME + self.host
-
-    @property
-    def host(self) -> str:
-        # Use mark sanitized to prevent false positives from Pysa thinking that
-        # the host is user controlled.
-        return mark_sanitized(self.host_for_subdomain(self.subdomain))
-
-    @staticmethod
-    def host_for_subdomain(subdomain: str) -> str:
-        if subdomain == Realm.SUBDOMAIN_FOR_ROOT_DOMAIN:
-            return settings.EXTERNAL_HOST
-        default_host = f"{subdomain}.{settings.EXTERNAL_HOST}"
-        return settings.REALM_HOSTS.get(subdomain, default_host)
-
-    @property
-    def is_zephyr_mirror_realm(self) -> bool:
-        return self.string_id == "zephyr"
-
-    @property
-    def webathena_enabled(self) -> bool:
-        return self.is_zephyr_mirror_realm
-
-    @property
-    def presence_disabled(self) -> bool:
-        return self.is_zephyr_mirror_realm
-
-    def web_public_streams_enabled(self) -> bool:
-        if not settings.WEB_PUBLIC_STREAMS_ENABLED:
-            # To help protect against accidentally web-public streams in
-            # self-hosted servers, we require the feature to be enabled at
-            # the server level before it is available to users.
-            return False
-
-        if self.plan_type == Realm.PLAN_TYPE_LIMITED:
-            # In Zulip Cloud, we also require a paid or sponsored
-            # plan, to protect against the spam/abuse attacks that
-            # target every open Internet service that can host files.
-            return False
-
-        if not self.enable_spectator_access:
-            return False
-
-        return True
-
-    def has_web_public_streams(self) -> bool:
-        if not self.web_public_streams_enabled():
-            return False
-
-        from zerver.lib.streams import get_web_public_streams_queryset
-
-        return get_web_public_streams_queryset(self).exists()
-
-    def allow_web_public_streams_access(self) -> bool:
-        """
-        If any of the streams in the realm is web
-        public and `enable_spectator_access` and
-        settings.WEB_PUBLIC_STREAMS_ENABLED is True,
-        then the Realm is web-public.
-        """
-        return self.has_web_public_streams()
-
-
-post_save.connect(flush_realm, sender=Realm)
-
-
-# We register realm cache flushing in a duplicate way to be run both
-# pre_delete and post_delete on purpose:
-# 1. pre_delete is needed because flush_realm wants to flush the UserProfile caches,
-#    and UserProfile objects are deleted via on_delete=CASCADE before the post_delete handler
-#    is called, which results in the `flush_realm` logic not having access to the details
-#    for the deleted users if called at that time.
-# 2. post_delete is run as a precaution to reduce the risk of races where items might be
-#    added to the cache after the pre_delete handler but before the save.
-#    Note that it does not eliminate this risk, not least because it only flushes
-#    the realm cache, and not the user caches, for the reasons explained above.
-def realm_pre_and_post_delete_handler(*, instance: Realm, **kwargs: object) -> None:
-    # This would be better as a functools.partial, but for some reason
-    # Django doesn't call it even when it's registered as a post_delete handler.
-    flush_realm(instance=instance, from_deletion=True)
-
-
-pre_delete.connect(realm_pre_and_post_delete_handler, sender=Realm)
-post_delete.connect(realm_pre_and_post_delete_handler, sender=Realm)
-
-
-def get_realm(string_id: str) -> Realm:
-    return Realm.objects.get(string_id=string_id)
-
-
-def get_realm_by_id(realm_id: int) -> Realm:
-    return Realm.objects.get(id=realm_id)
-
-
-def name_changes_disabled(realm: Optional[Realm]) -> bool:
-    if realm is None:
-        return settings.NAME_CHANGES_DISABLED
-    return settings.NAME_CHANGES_DISABLED or realm.name_changes_disabled
-
-
-def avatar_changes_disabled(realm: Realm) -> bool:
-    return settings.AVATAR_CHANGES_DISABLED or realm.avatar_changes_disabled
-
-
-def get_org_type_display_name(org_type: int) -> str:
-    for realm_type_details in Realm.ORG_TYPES.values():
-        if realm_type_details["id"] == org_type:
-            return realm_type_details["name"]
-
-    return ""
-
-
-class RealmDomain(models.Model):
-    """For an organization with emails_restricted_to_domains enabled, the list of
-    allowed domains"""
-
-    realm = models.ForeignKey(Realm, on_delete=CASCADE)
-    # should always be stored lowercase
-    domain = models.CharField(max_length=80, db_index=True)
-    allow_subdomains = models.BooleanField(default=False)
-
-    class Meta:
-        unique_together = ("realm", "domain")
-
-
-class DomainNotAllowedForRealmError(Exception):
-    pass
-
-
-class DisposableEmailError(Exception):
-    pass
-
-
-class EmailContainsPlusError(Exception):
-    pass
-
-
-class RealmDomainDict(TypedDict):
-    domain: str
-    allow_subdomains: bool
-
-
-def get_realm_domains(realm: Realm) -> List[RealmDomainDict]:
-    return list(realm.realmdomain_set.values("domain", "allow_subdomains"))
-
-
 class RealmEmoji(models.Model):
     author = models.ForeignKey(
         "UserProfile",
@@ -4061,30 +3088,6 @@ class BotConfigData(models.Model):
         unique_together = ("bot_profile", "key")
 
 
-class InvalidFakeEmailDomainError(Exception):
-    pass
-
-
-def get_fake_email_domain(realm_host: str) -> str:
-    try:
-        # Check that realm.host can be used to form valid email addresses.
-        validate_email(Address(username="bot", domain=realm_host).addr_spec)
-        return realm_host
-    except ValidationError:
-        pass
-
-    try:
-        # Check that the fake email domain can be used to form valid email addresses.
-        validate_email(Address(username="bot", domain=settings.FAKE_EMAIL_DOMAIN).addr_spec)
-    except ValidationError:
-        raise InvalidFakeEmailDomainError(
-            settings.FAKE_EMAIL_DOMAIN + " is not a valid domain. "
-            "Consider setting the FAKE_EMAIL_DOMAIN setting."
-        )
-
-    return settings.FAKE_EMAIL_DOMAIN
-
-
 class AlertWord(models.Model):
     # Realm isn't necessary, but it's a nice denormalization.  Users
     # never move to another realm, so it's static, and having Realm
diff --git a/zerver/models/realms.py b/zerver/models/realms.py
new file mode 100644
index 0000000000..f243e5dd8e
--- /dev/null
+++ b/zerver/models/realms.py
@@ -0,0 +1,1019 @@
+from email.headerregistry import Address
+from enum import Enum
+from typing import TYPE_CHECKING, Dict, List, Optional, Tuple, TypedDict, Union
+from uuid import uuid4
+
+import django.contrib.auth
+from django.conf import settings
+from django.core.exceptions import ValidationError
+from django.core.validators import validate_email
+from django.db import models
+from django.db.models import CASCADE, Q, QuerySet, Sum
+from django.db.models.signals import post_delete, post_save, pre_delete
+from django.utils.timezone import now as timezone_now
+from django.utils.translation import gettext_lazy
+from typing_extensions import override
+
+from zerver.lib.cache import cache_with_key, flush_realm, get_realm_used_upload_space_cache_key
+from zerver.lib.exceptions import JsonableError
+from zerver.lib.pysa import mark_sanitized
+from zerver.lib.types import GroupPermissionSetting
+from zerver.lib.utils import generate_api_key
+from zerver.models.constants import MAX_LANGUAGE_ID_LENGTH
+from zerver.models.groups import SystemGroups
+from zerver.models.users import UserProfile
+
+if TYPE_CHECKING:
+    # We use ModelBackend only for typing. Importing it otherwise causes circular dependency.
+    from django.contrib.auth.backends import ModelBackend
+
+    from zerver.models import Stream
+
+SECONDS_PER_DAY = 86400
+
+
+# This simple call-once caching saves ~500us in auth_enabled_helper,
+# which is a significant optimization for common_context.  Note that
+# these values cannot change in a running production system, but do
+# regularly change within unit tests; we address the latter by calling
+# clear_supported_auth_backends_cache in our standard tearDown code.
+supported_backends: Optional[List["ModelBackend"]] = None
+
+
+def supported_auth_backends() -> List["ModelBackend"]:
+    global supported_backends
+    # Caching temporarily disabled for debugging
+    supported_backends = django.contrib.auth.get_backends()
+    assert supported_backends is not None
+    return supported_backends
+
+
+def clear_supported_auth_backends_cache() -> None:
+    global supported_backends
+    supported_backends = None
+
+
+class RealmAuthenticationMethod(models.Model):
+    """
+    Tracks which authentication backends are enabled for a realm.
+    An enabled backend is represented in this table a row with appropriate
+    .realm value and .name matching the name of the target backend in the
+    AUTH_BACKEND_NAME_MAP dict.
+    """
+
+    realm = models.ForeignKey("Realm", on_delete=CASCADE, db_index=True)
+    name = models.CharField(max_length=80)
+
+    class Meta:
+        unique_together = ("realm", "name")
+
+
+def generate_realm_uuid_owner_secret() -> str:
+    token = generate_api_key()
+
+    # We include a prefix to facilitate scanning for accidental
+    # disclosure of secrets e.g. in Github commit pushes.
+    return f"zuliprealm_{token}"
+
+
+class OrgTypeEnum(Enum):
+    Unspecified = 0
+    Business = 10
+    OpenSource = 20
+    EducationNonProfit = 30
+    Education = 35
+    Research = 40
+    Event = 50
+    NonProfit = 60
+    Government = 70
+    PoliticalGroup = 80
+    Community = 90
+    Personal = 100
+    Other = 1000
+
+
+class OrgTypeDict(TypedDict):
+    name: str
+    id: int
+    hidden: bool
+    display_order: int
+    onboarding_zulip_guide_url: Optional[str]
+
+
+class Realm(models.Model):  # type: ignore[django-manager-missing] # django-stubs cannot resolve the custom CTEManager yet https://github.com/typeddjango/django-stubs/issues/1023
+    MAX_REALM_NAME_LENGTH = 40
+    MAX_REALM_DESCRIPTION_LENGTH = 1000
+    MAX_REALM_SUBDOMAIN_LENGTH = 40
+    MAX_REALM_REDIRECT_URL_LENGTH = 128
+
+    INVITES_STANDARD_REALM_DAILY_MAX = 3000
+    MESSAGE_VISIBILITY_LIMITED = 10000
+    SUBDOMAIN_FOR_ROOT_DOMAIN = ""
+    WILDCARD_MENTION_THRESHOLD = 15
+
+    # User-visible display name and description used on e.g. the organization homepage
+    name = models.CharField(max_length=MAX_REALM_NAME_LENGTH)
+    description = models.TextField(default="")
+
+    # A short, identifier-like name for the organization.  Used in subdomains;
+    # e.g. on a server at example.com, an org with string_id `foo` is reached
+    # at `foo.example.com`.
+    string_id = models.CharField(max_length=MAX_REALM_SUBDOMAIN_LENGTH, unique=True)
+
+    # uuid and a secret for the sake of per-realm authentication with the push notification
+    # bouncer.
+    uuid = models.UUIDField(default=uuid4, unique=True)
+    uuid_owner_secret = models.TextField(default=generate_realm_uuid_owner_secret)
+    # Whether push notifications are working for this realm, and
+    # whether there is a specific date at which we expect that to
+    # cease to be the case.
+    push_notifications_enabled = models.BooleanField(default=False, db_index=True)
+    push_notifications_enabled_end_timestamp = models.DateTimeField(default=None, null=True)
+
+    date_created = models.DateTimeField(default=timezone_now)
+    demo_organization_scheduled_deletion_date = models.DateTimeField(default=None, null=True)
+    deactivated = models.BooleanField(default=False)
+
+    # Redirect URL if the Realm has moved to another server
+    deactivated_redirect = models.URLField(max_length=MAX_REALM_REDIRECT_URL_LENGTH, null=True)
+
+    # See RealmDomain for the domains that apply for a given organization.
+    emails_restricted_to_domains = models.BooleanField(default=False)
+
+    invite_required = models.BooleanField(default=True)
+
+    _max_invites = models.IntegerField(null=True, db_column="max_invites")
+    disallow_disposable_email_addresses = models.BooleanField(default=True)
+
+    # Allow users to access web-public streams without login. This
+    # setting also controls API access of web-public streams.
+    enable_spectator_access = models.BooleanField(default=False)
+
+    # Whether organization has given permission to be advertised in the
+    # Zulip communities directory.
+    want_advertise_in_communities_directory = models.BooleanField(default=False, db_index=True)
+
+    # Whether the organization has enabled inline image and URL previews.
+    inline_image_preview = models.BooleanField(default=True)
+    inline_url_embed_preview = models.BooleanField(default=False)
+
+    # Whether digest emails are enabled for the organization.
+    digest_emails_enabled = models.BooleanField(default=False)
+    # Day of the week on which the digest is sent (default: Tuesday).
+    digest_weekday = models.SmallIntegerField(default=1)
+
+    send_welcome_emails = models.BooleanField(default=True)
+    message_content_allowed_in_email_notifications = models.BooleanField(default=True)
+
+    mandatory_topics = models.BooleanField(default=False)
+
+    name_changes_disabled = models.BooleanField(default=False)
+    email_changes_disabled = models.BooleanField(default=False)
+    avatar_changes_disabled = models.BooleanField(default=False)
+
+    POLICY_MEMBERS_ONLY = 1
+    POLICY_ADMINS_ONLY = 2
+    POLICY_FULL_MEMBERS_ONLY = 3
+    POLICY_MODERATORS_ONLY = 4
+    POLICY_EVERYONE = 5
+    POLICY_NOBODY = 6
+    POLICY_OWNERS_ONLY = 7
+
+    COMMON_POLICY_TYPES = [
+        POLICY_MEMBERS_ONLY,
+        POLICY_ADMINS_ONLY,
+        POLICY_FULL_MEMBERS_ONLY,
+        POLICY_MODERATORS_ONLY,
+    ]
+
+    COMMON_MESSAGE_POLICY_TYPES = [
+        POLICY_MEMBERS_ONLY,
+        POLICY_ADMINS_ONLY,
+        POLICY_FULL_MEMBERS_ONLY,
+        POLICY_MODERATORS_ONLY,
+        POLICY_EVERYONE,
+    ]
+
+    INVITE_TO_REALM_POLICY_TYPES = [
+        POLICY_MEMBERS_ONLY,
+        POLICY_ADMINS_ONLY,
+        POLICY_FULL_MEMBERS_ONLY,
+        POLICY_MODERATORS_ONLY,
+        POLICY_NOBODY,
+    ]
+
+    # We don't allow granting roles less than Moderator access to
+    # create web-public streams, since it's a sensitive feature that
+    # can be used to send spam.
+    CREATE_WEB_PUBLIC_STREAM_POLICY_TYPES = [
+        POLICY_ADMINS_ONLY,
+        POLICY_MODERATORS_ONLY,
+        POLICY_OWNERS_ONLY,
+        POLICY_NOBODY,
+    ]
+
+    EDIT_TOPIC_POLICY_TYPES = [
+        POLICY_MEMBERS_ONLY,
+        POLICY_ADMINS_ONLY,
+        POLICY_FULL_MEMBERS_ONLY,
+        POLICY_MODERATORS_ONLY,
+        POLICY_EVERYONE,
+        POLICY_NOBODY,
+    ]
+
+    MOVE_MESSAGES_BETWEEN_STREAMS_POLICY_TYPES = INVITE_TO_REALM_POLICY_TYPES
+
+    DEFAULT_MOVE_MESSAGE_LIMIT_SECONDS = 7 * SECONDS_PER_DAY
+
+    move_messages_within_stream_limit_seconds = models.PositiveIntegerField(
+        default=DEFAULT_MOVE_MESSAGE_LIMIT_SECONDS, null=True
+    )
+
+    move_messages_between_streams_limit_seconds = models.PositiveIntegerField(
+        default=DEFAULT_MOVE_MESSAGE_LIMIT_SECONDS, null=True
+    )
+
+    # Who in the organization is allowed to add custom emojis.
+    add_custom_emoji_policy = models.PositiveSmallIntegerField(default=POLICY_MEMBERS_ONLY)
+
+    # Who in the organization is allowed to create streams.
+    create_public_stream_policy = models.PositiveSmallIntegerField(default=POLICY_MEMBERS_ONLY)
+    create_private_stream_policy = models.PositiveSmallIntegerField(default=POLICY_MEMBERS_ONLY)
+    create_web_public_stream_policy = models.PositiveSmallIntegerField(default=POLICY_OWNERS_ONLY)
+
+    # Who in the organization is allowed to delete messages they themselves sent.
+    delete_own_message_policy = models.PositiveSmallIntegerField(default=POLICY_ADMINS_ONLY)
+
+    # Who in the organization is allowed to edit topics of any message.
+    edit_topic_policy = models.PositiveSmallIntegerField(default=POLICY_EVERYONE)
+
+    # Who in the organization is allowed to invite other users to organization.
+    invite_to_realm_policy = models.PositiveSmallIntegerField(default=POLICY_MEMBERS_ONLY)
+
+    # UserGroup whose members are allowed to create invite link.
+    create_multiuse_invite_group = models.ForeignKey(
+        "UserGroup", on_delete=models.RESTRICT, related_name="+"
+    )
+
+    # on_delete field here is set to RESTRICT because we don't want to allow
+    # deleting a user group in case it is referenced by this setting.
+    # We are not using PROTECT since we want to allow deletion of user groups
+    # when realm itself is deleted.
+    can_access_all_users_group = models.ForeignKey(
+        "UserGroup", on_delete=models.RESTRICT, related_name="+"
+    )
+
+    # Who in the organization is allowed to invite other users to streams.
+    invite_to_stream_policy = models.PositiveSmallIntegerField(default=POLICY_MEMBERS_ONLY)
+
+    # Who in the organization is allowed to move messages between streams.
+    move_messages_between_streams_policy = models.PositiveSmallIntegerField(
+        default=POLICY_ADMINS_ONLY
+    )
+
+    user_group_edit_policy = models.PositiveSmallIntegerField(default=POLICY_MEMBERS_ONLY)
+
+    PRIVATE_MESSAGE_POLICY_UNLIMITED = 1
+    PRIVATE_MESSAGE_POLICY_DISABLED = 2
+    private_message_policy = models.PositiveSmallIntegerField(
+        default=PRIVATE_MESSAGE_POLICY_UNLIMITED
+    )
+    PRIVATE_MESSAGE_POLICY_TYPES = [
+        PRIVATE_MESSAGE_POLICY_UNLIMITED,
+        PRIVATE_MESSAGE_POLICY_DISABLED,
+    ]
+
+    # Global policy for who is allowed to use wildcard mentions in
+    # streams with a large number of subscribers.  Anyone can use
+    # wildcard mentions in small streams regardless of this setting.
+    WILDCARD_MENTION_POLICY_EVERYONE = 1
+    WILDCARD_MENTION_POLICY_MEMBERS = 2
+    WILDCARD_MENTION_POLICY_FULL_MEMBERS = 3
+    WILDCARD_MENTION_POLICY_ADMINS = 5
+    WILDCARD_MENTION_POLICY_NOBODY = 6
+    WILDCARD_MENTION_POLICY_MODERATORS = 7
+    wildcard_mention_policy = models.PositiveSmallIntegerField(
+        default=WILDCARD_MENTION_POLICY_ADMINS,
+    )
+    WILDCARD_MENTION_POLICY_TYPES = [
+        WILDCARD_MENTION_POLICY_EVERYONE,
+        WILDCARD_MENTION_POLICY_MEMBERS,
+        WILDCARD_MENTION_POLICY_FULL_MEMBERS,
+        WILDCARD_MENTION_POLICY_ADMINS,
+        WILDCARD_MENTION_POLICY_NOBODY,
+        WILDCARD_MENTION_POLICY_MODERATORS,
+    ]
+
+    # Threshold in days for new users to create streams, and potentially take
+    # some other actions.
+    waiting_period_threshold = models.PositiveIntegerField(default=0)
+
+    DEFAULT_MESSAGE_CONTENT_DELETE_LIMIT_SECONDS = (
+        600  # if changed, also change in admin.js, setting_org.js
+    )
+    MESSAGE_TIME_LIMIT_SETTING_SPECIAL_VALUES_MAP = {
+        "unlimited": None,
+    }
+    message_content_delete_limit_seconds = models.PositiveIntegerField(
+        default=DEFAULT_MESSAGE_CONTENT_DELETE_LIMIT_SECONDS, null=True
+    )
+
+    allow_message_editing = models.BooleanField(default=True)
+    DEFAULT_MESSAGE_CONTENT_EDIT_LIMIT_SECONDS = (
+        600  # if changed, also change in admin.js, setting_org.js
+    )
+    message_content_edit_limit_seconds = models.PositiveIntegerField(
+        default=DEFAULT_MESSAGE_CONTENT_EDIT_LIMIT_SECONDS, null=True
+    )
+
+    # Whether users have access to message edit history
+    allow_edit_history = models.BooleanField(default=True)
+
+    # Defaults for new users
+    default_language = models.CharField(default="en", max_length=MAX_LANGUAGE_ID_LENGTH)
+
+    DEFAULT_NOTIFICATION_STREAM_NAME = "general"
+    INITIAL_PRIVATE_STREAM_NAME = "core team"
+    STREAM_EVENTS_NOTIFICATION_TOPIC = gettext_lazy("stream events")
+    notifications_stream = models.ForeignKey(
+        "Stream",
+        related_name="+",
+        null=True,
+        blank=True,
+        on_delete=models.SET_NULL,
+    )
+    signup_notifications_stream = models.ForeignKey(
+        "Stream",
+        related_name="+",
+        null=True,
+        blank=True,
+        on_delete=models.SET_NULL,
+    )
+
+    MESSAGE_RETENTION_SPECIAL_VALUES_MAP = {
+        "unlimited": -1,
+    }
+    # For old messages being automatically deleted
+    message_retention_days = models.IntegerField(null=False, default=-1)
+
+    # When non-null, all but the latest this many messages in the organization
+    # are inaccessible to users (but not deleted).
+    message_visibility_limit = models.IntegerField(null=True)
+
+    # Messages older than this message ID in the organization are inaccessible.
+    first_visible_message_id = models.IntegerField(default=0)
+
+    # Valid org types
+    ORG_TYPES: Dict[str, OrgTypeDict] = {
+        "unspecified": {
+            "name": "Unspecified",
+            "id": OrgTypeEnum.Unspecified.value,
+            "hidden": True,
+            "display_order": 0,
+            "onboarding_zulip_guide_url": None,
+        },
+        "business": {
+            "name": "Business",
+            "id": OrgTypeEnum.Business.value,
+            "hidden": False,
+            "display_order": 1,
+            "onboarding_zulip_guide_url": "https://zulip.com/for/business/",
+        },
+        "opensource": {
+            "name": "Open-source project",
+            "id": OrgTypeEnum.OpenSource.value,
+            "hidden": False,
+            "display_order": 2,
+            "onboarding_zulip_guide_url": "https://zulip.com/for/open-source/",
+        },
+        "education_nonprofit": {
+            "name": "Education (non-profit)",
+            "id": OrgTypeEnum.EducationNonProfit.value,
+            "hidden": False,
+            "display_order": 3,
+            "onboarding_zulip_guide_url": "https://zulip.com/for/education/",
+        },
+        "education": {
+            "name": "Education (for-profit)",
+            "id": OrgTypeEnum.Education.value,
+            "hidden": False,
+            "display_order": 4,
+            "onboarding_zulip_guide_url": "https://zulip.com/for/education/",
+        },
+        "research": {
+            "name": "Research",
+            "id": OrgTypeEnum.Research.value,
+            "hidden": False,
+            "display_order": 5,
+            "onboarding_zulip_guide_url": "https://zulip.com/for/research/",
+        },
+        "event": {
+            "name": "Event or conference",
+            "id": OrgTypeEnum.Event.value,
+            "hidden": False,
+            "display_order": 6,
+            "onboarding_zulip_guide_url": "https://zulip.com/for/events/",
+        },
+        "nonprofit": {
+            "name": "Non-profit (registered)",
+            "id": OrgTypeEnum.NonProfit.value,
+            "hidden": False,
+            "display_order": 7,
+            "onboarding_zulip_guide_url": "https://zulip.com/for/communities/",
+        },
+        "government": {
+            "name": "Government",
+            "id": OrgTypeEnum.Government.value,
+            "hidden": False,
+            "display_order": 8,
+            "onboarding_zulip_guide_url": None,
+        },
+        "political_group": {
+            "name": "Political group",
+            "id": OrgTypeEnum.PoliticalGroup.value,
+            "hidden": False,
+            "display_order": 9,
+            "onboarding_zulip_guide_url": None,
+        },
+        "community": {
+            "name": "Community",
+            "id": OrgTypeEnum.Community.value,
+            "hidden": False,
+            "display_order": 10,
+            "onboarding_zulip_guide_url": "https://zulip.com/for/communities/",
+        },
+        "personal": {
+            "name": "Personal",
+            "id": OrgTypeEnum.Personal.value,
+            "hidden": False,
+            "display_order": 100,
+            "onboarding_zulip_guide_url": None,
+        },
+        "other": {
+            "name": "Other",
+            "id": OrgTypeEnum.Other.value,
+            "hidden": False,
+            "display_order": 1000,
+            "onboarding_zulip_guide_url": None,
+        },
+    }
+
+    ORG_TYPE_IDS: List[int] = [t["id"] for t in ORG_TYPES.values()]
+
+    org_type = models.PositiveSmallIntegerField(
+        default=ORG_TYPES["unspecified"]["id"],
+        choices=[(t["id"], t["name"]) for t in ORG_TYPES.values()],
+    )
+
+    UPGRADE_TEXT_STANDARD = gettext_lazy("Available on Zulip Cloud Standard. Upgrade to access.")
+    UPGRADE_TEXT_PLUS = gettext_lazy("Available on Zulip Cloud Plus. Upgrade to access.")
+    # plan_type controls various features around resource/feature
+    # limitations for a Zulip organization on multi-tenant installations
+    # like Zulip Cloud.
+    PLAN_TYPE_SELF_HOSTED = 1
+    PLAN_TYPE_LIMITED = 2
+    PLAN_TYPE_STANDARD = 3
+    PLAN_TYPE_STANDARD_FREE = 4
+    PLAN_TYPE_PLUS = 10
+
+    # Used for creating realms with different plan types.
+    ALL_PLAN_TYPES = {
+        PLAN_TYPE_SELF_HOSTED: "self-hosted-plan",
+        PLAN_TYPE_LIMITED: "limited-plan",
+        PLAN_TYPE_STANDARD: "standard-plan",
+        PLAN_TYPE_STANDARD_FREE: "standard-free-plan",
+        PLAN_TYPE_PLUS: "plus-plan",
+    }
+    plan_type = models.PositiveSmallIntegerField(default=PLAN_TYPE_SELF_HOSTED)
+
+    # This value is also being used in web/src/settings_bots.bot_creation_policy_values.
+    # On updating it here, update it there as well.
+    BOT_CREATION_EVERYONE = 1
+    BOT_CREATION_LIMIT_GENERIC_BOTS = 2
+    BOT_CREATION_ADMINS_ONLY = 3
+    bot_creation_policy = models.PositiveSmallIntegerField(default=BOT_CREATION_EVERYONE)
+    BOT_CREATION_POLICY_TYPES = [
+        BOT_CREATION_EVERYONE,
+        BOT_CREATION_LIMIT_GENERIC_BOTS,
+        BOT_CREATION_ADMINS_ONLY,
+    ]
+
+    # See upload_quota_bytes; don't interpret upload_quota_gb directly.
+    UPLOAD_QUOTA_LIMITED = 5
+    UPLOAD_QUOTA_STANDARD = 50
+    upload_quota_gb = models.IntegerField(null=True)
+
+    VIDEO_CHAT_PROVIDERS = {
+        "disabled": {
+            "name": "None",
+            "id": 0,
+        },
+        "jitsi_meet": {
+            "name": "Jitsi Meet",
+            "id": 1,
+        },
+        # ID 2 was used for the now-deleted Google Hangouts.
+        # ID 3 reserved for optional Zoom, see below.
+        # ID 4 reserved for optional BigBlueButton, see below.
+    }
+
+    if settings.VIDEO_ZOOM_CLIENT_ID is not None and settings.VIDEO_ZOOM_CLIENT_SECRET is not None:
+        VIDEO_CHAT_PROVIDERS["zoom"] = {
+            "name": "Zoom",
+            "id": 3,
+        }
+
+    if settings.BIG_BLUE_BUTTON_SECRET is not None and settings.BIG_BLUE_BUTTON_URL is not None:
+        VIDEO_CHAT_PROVIDERS["big_blue_button"] = {"name": "BigBlueButton", "id": 4}
+
+    video_chat_provider = models.PositiveSmallIntegerField(
+        default=VIDEO_CHAT_PROVIDERS["jitsi_meet"]["id"]
+    )
+
+    JITSI_SERVER_SPECIAL_VALUES_MAP = {"default": None}
+    jitsi_server_url = models.URLField(null=True, default=None)
+
+    # Please access this via get_giphy_rating_options.
+    GIPHY_RATING_OPTIONS = {
+        "disabled": {
+            "name": gettext_lazy("GIPHY integration disabled"),
+            "id": 0,
+        },
+        # Source: https://github.com/Giphy/giphy-js/blob/master/packages/fetch-api/README.md#shared-options
+        "y": {
+            "name": gettext_lazy("Allow GIFs rated Y (Very young audience)"),
+            "id": 1,
+        },
+        "g": {
+            "name": gettext_lazy("Allow GIFs rated G (General audience)"),
+            "id": 2,
+        },
+        "pg": {
+            "name": gettext_lazy("Allow GIFs rated PG (Parental guidance)"),
+            "id": 3,
+        },
+        "pg-13": {
+            "name": gettext_lazy("Allow GIFs rated PG-13 (Parental guidance - under 13)"),
+            "id": 4,
+        },
+        "r": {
+            "name": gettext_lazy("Allow GIFs rated R (Restricted)"),
+            "id": 5,
+        },
+    }
+
+    # maximum rating of the GIFs that will be retrieved from GIPHY
+    giphy_rating = models.PositiveSmallIntegerField(default=GIPHY_RATING_OPTIONS["g"]["id"])
+
+    default_code_block_language = models.TextField(default="")
+
+    # Whether read receipts are enabled in the organization. If disabled,
+    # they will not be available regardless of users' personal settings.
+    enable_read_receipts = models.BooleanField(default=False)
+
+    # Whether clients should display "(guest)" after names of guest users.
+    enable_guest_user_indicator = models.BooleanField(default=True)
+
+    # Define the types of the various automatically managed properties
+    property_types: Dict[str, Union[type, Tuple[type, ...]]] = dict(
+        add_custom_emoji_policy=int,
+        allow_edit_history=bool,
+        allow_message_editing=bool,
+        avatar_changes_disabled=bool,
+        bot_creation_policy=int,
+        create_private_stream_policy=int,
+        create_public_stream_policy=int,
+        create_web_public_stream_policy=int,
+        default_code_block_language=str,
+        default_language=str,
+        delete_own_message_policy=int,
+        description=str,
+        digest_emails_enabled=bool,
+        digest_weekday=int,
+        disallow_disposable_email_addresses=bool,
+        edit_topic_policy=int,
+        email_changes_disabled=bool,
+        emails_restricted_to_domains=bool,
+        enable_guest_user_indicator=bool,
+        enable_read_receipts=bool,
+        enable_spectator_access=bool,
+        giphy_rating=int,
+        inline_image_preview=bool,
+        inline_url_embed_preview=bool,
+        invite_required=bool,
+        invite_to_realm_policy=int,
+        invite_to_stream_policy=int,
+        jitsi_server_url=(str, type(None)),
+        mandatory_topics=bool,
+        message_content_allowed_in_email_notifications=bool,
+        message_content_edit_limit_seconds=(int, type(None)),
+        message_content_delete_limit_seconds=(int, type(None)),
+        move_messages_between_streams_limit_seconds=(int, type(None)),
+        move_messages_within_stream_limit_seconds=(int, type(None)),
+        message_retention_days=(int, type(None)),
+        move_messages_between_streams_policy=int,
+        name=str,
+        name_changes_disabled=bool,
+        private_message_policy=int,
+        push_notifications_enabled=bool,
+        send_welcome_emails=bool,
+        user_group_edit_policy=int,
+        video_chat_provider=int,
+        waiting_period_threshold=int,
+        want_advertise_in_communities_directory=bool,
+        wildcard_mention_policy=int,
+    )
+
+    REALM_PERMISSION_GROUP_SETTINGS: Dict[str, GroupPermissionSetting] = dict(
+        create_multiuse_invite_group=GroupPermissionSetting(
+            require_system_group=True,
+            allow_internet_group=False,
+            allow_owners_group=False,
+            allow_nobody_group=True,
+            allow_everyone_group=False,
+            default_group_name=SystemGroups.ADMINISTRATORS,
+            id_field_name="create_multiuse_invite_group_id",
+        ),
+        can_access_all_users_group=GroupPermissionSetting(
+            require_system_group=True,
+            allow_internet_group=False,
+            allow_owners_group=False,
+            allow_nobody_group=False,
+            allow_everyone_group=True,
+            default_group_name=SystemGroups.EVERYONE,
+            id_field_name="can_access_all_users_group_id",
+            allowed_system_groups=[SystemGroups.EVERYONE, SystemGroups.MEMBERS],
+        ),
+    )
+
+    DIGEST_WEEKDAY_VALUES = [0, 1, 2, 3, 4, 5, 6]
+
+    # Icon is the square mobile icon.
+    ICON_FROM_GRAVATAR = "G"
+    ICON_UPLOADED = "U"
+    ICON_SOURCES = (
+        (ICON_FROM_GRAVATAR, "Hosted by Gravatar"),
+        (ICON_UPLOADED, "Uploaded by administrator"),
+    )
+    icon_source = models.CharField(
+        default=ICON_FROM_GRAVATAR,
+        choices=ICON_SOURCES,
+        max_length=1,
+    )
+    icon_version = models.PositiveSmallIntegerField(default=1)
+
+    # Logo is the horizontal logo we show in top-left of web app navbar UI.
+    LOGO_DEFAULT = "D"
+    LOGO_UPLOADED = "U"
+    LOGO_SOURCES = (
+        (LOGO_DEFAULT, "Default to Zulip"),
+        (LOGO_UPLOADED, "Uploaded by administrator"),
+    )
+    logo_source = models.CharField(
+        default=LOGO_DEFAULT,
+        choices=LOGO_SOURCES,
+        max_length=1,
+    )
+    logo_version = models.PositiveSmallIntegerField(default=1)
+
+    night_logo_source = models.CharField(
+        default=LOGO_DEFAULT,
+        choices=LOGO_SOURCES,
+        max_length=1,
+    )
+    night_logo_version = models.PositiveSmallIntegerField(default=1)
+
+    @override
+    def __str__(self) -> str:
+        return f"{self.string_id} {self.id}"
+
+    def get_giphy_rating_options(self) -> Dict[str, Dict[str, object]]:
+        """Wrapper function for GIPHY_RATING_OPTIONS that ensures evaluation
+        of the lazily evaluated `name` field without modifying the original."""
+        return {
+            rating_type: {"name": str(rating["name"]), "id": rating["id"]}
+            for rating_type, rating in self.GIPHY_RATING_OPTIONS.items()
+        }
+
+    def authentication_methods_dict(self) -> Dict[str, bool]:
+        """Returns the mapping from authentication flags to their status,
+        showing only those authentication flags that are supported on
+        the current server (i.e. if EmailAuthBackend is not configured
+        on the server, this will not return an entry for "Email")."""
+        # This mapping needs to be imported from here due to the cyclic
+        # dependency.
+        from zproject.backends import AUTH_BACKEND_NAME_MAP, all_implemented_backend_names
+
+        ret: Dict[str, bool] = {}
+        supported_backends = [type(backend) for backend in supported_auth_backends()]
+
+        for backend_name in all_implemented_backend_names():
+            backend_class = AUTH_BACKEND_NAME_MAP[backend_name]
+            if backend_class in supported_backends:
+                ret[backend_name] = False
+        for realm_authentication_method in RealmAuthenticationMethod.objects.filter(
+            realm_id=self.id
+        ):
+            backend_class = AUTH_BACKEND_NAME_MAP[realm_authentication_method.name]
+            if backend_class in supported_backends:
+                ret[realm_authentication_method.name] = True
+        return ret
+
+    def get_admin_users_and_bots(
+        self, include_realm_owners: bool = True
+    ) -> QuerySet["UserProfile"]:
+        """Use this in contexts where we want administrative users as well as
+        bots with administrator privileges, like send_event calls for
+        notifications to all administrator users.
+        """
+        if include_realm_owners:
+            roles = [UserProfile.ROLE_REALM_ADMINISTRATOR, UserProfile.ROLE_REALM_OWNER]
+        else:
+            roles = [UserProfile.ROLE_REALM_ADMINISTRATOR]
+
+        return UserProfile.objects.filter(
+            realm=self,
+            is_active=True,
+            role__in=roles,
+        )
+
+    def get_human_admin_users(self, include_realm_owners: bool = True) -> QuerySet["UserProfile"]:
+        """Use this in contexts where we want only human users with
+        administrative privileges, like sending an email to all of a
+        realm's administrators (bots don't have real email addresses).
+        """
+        if include_realm_owners:
+            roles = [UserProfile.ROLE_REALM_ADMINISTRATOR, UserProfile.ROLE_REALM_OWNER]
+        else:
+            roles = [UserProfile.ROLE_REALM_ADMINISTRATOR]
+
+        return UserProfile.objects.filter(
+            realm=self,
+            is_bot=False,
+            is_active=True,
+            role__in=roles,
+        )
+
+    def get_human_billing_admin_and_realm_owner_users(self) -> QuerySet["UserProfile"]:
+        return UserProfile.objects.filter(
+            Q(role=UserProfile.ROLE_REALM_OWNER) | Q(is_billing_admin=True),
+            realm=self,
+            is_bot=False,
+            is_active=True,
+        )
+
+    def get_active_users(self) -> QuerySet["UserProfile"]:
+        return UserProfile.objects.filter(realm=self, is_active=True)
+
+    def get_first_human_user(self) -> Optional["UserProfile"]:
+        """A useful value for communications with newly created realms.
+        Has a few fundamental limitations:
+
+        * Its value will be effectively random for realms imported from Slack or
+          other third-party tools.
+        * The user may be deactivated, etc., so it's not something that's useful
+          for features, permissions, etc.
+        """
+        return UserProfile.objects.filter(realm=self, is_bot=False).order_by("id").first()
+
+    def get_human_owner_users(self) -> QuerySet["UserProfile"]:
+        return UserProfile.objects.filter(
+            realm=self, is_bot=False, role=UserProfile.ROLE_REALM_OWNER, is_active=True
+        )
+
+    def get_bot_domain(self) -> str:
+        return get_fake_email_domain(self.host)
+
+    def get_notifications_stream(self) -> Optional["Stream"]:
+        if self.notifications_stream is not None and not self.notifications_stream.deactivated:
+            return self.notifications_stream
+        return None
+
+    def get_signup_notifications_stream(self) -> Optional["Stream"]:
+        if (
+            self.signup_notifications_stream is not None
+            and not self.signup_notifications_stream.deactivated
+        ):
+            return self.signup_notifications_stream
+        return None
+
+    @property
+    def max_invites(self) -> int:
+        if self._max_invites is None:
+            return settings.INVITES_DEFAULT_REALM_DAILY_MAX
+        return self._max_invites
+
+    @max_invites.setter
+    def max_invites(self, value: Optional[int]) -> None:
+        self._max_invites = value
+
+    def upload_quota_bytes(self) -> Optional[int]:
+        if self.upload_quota_gb is None:
+            return None
+        # We describe the quota to users in "GB" or "gigabytes", but actually apply
+        # it as gibibytes (GiB) to be a bit more generous in case of confusion.
+        return self.upload_quota_gb << 30
+
+    # `realm` instead of `self` here to make sure the parameters of the cache key
+    # function matches the original method.
+    @cache_with_key(
+        lambda realm: get_realm_used_upload_space_cache_key(realm.id), timeout=3600 * 24 * 7
+    )
+    def currently_used_upload_space_bytes(realm) -> int:  # noqa: N805
+        from zerver.models import Attachment
+
+        used_space = Attachment.objects.filter(realm=realm).aggregate(Sum("size"))["size__sum"]
+        if used_space is None:
+            return 0
+        return used_space
+
+    def ensure_not_on_limited_plan(self) -> None:
+        if self.plan_type == Realm.PLAN_TYPE_LIMITED:
+            raise JsonableError(str(self.UPGRADE_TEXT_STANDARD))
+
+    def can_enable_restricted_user_access_for_guests(self) -> None:
+        if self.plan_type not in [Realm.PLAN_TYPE_PLUS, Realm.PLAN_TYPE_SELF_HOSTED]:
+            raise JsonableError(str(self.UPGRADE_TEXT_PLUS))
+
+    @property
+    def subdomain(self) -> str:
+        return self.string_id
+
+    @property
+    def display_subdomain(self) -> str:
+        """Likely to be temporary function to avoid signup messages being sent
+        to an empty topic"""
+        if self.string_id == "":
+            return "."
+        return self.string_id
+
+    @property
+    def uri(self) -> str:
+        return settings.EXTERNAL_URI_SCHEME + self.host
+
+    @property
+    def host(self) -> str:
+        # Use mark sanitized to prevent false positives from Pysa thinking that
+        # the host is user controlled.
+        return mark_sanitized(self.host_for_subdomain(self.subdomain))
+
+    @staticmethod
+    def host_for_subdomain(subdomain: str) -> str:
+        if subdomain == Realm.SUBDOMAIN_FOR_ROOT_DOMAIN:
+            return settings.EXTERNAL_HOST
+        default_host = f"{subdomain}.{settings.EXTERNAL_HOST}"
+        return settings.REALM_HOSTS.get(subdomain, default_host)
+
+    @property
+    def is_zephyr_mirror_realm(self) -> bool:
+        return self.string_id == "zephyr"
+
+    @property
+    def webathena_enabled(self) -> bool:
+        return self.is_zephyr_mirror_realm
+
+    @property
+    def presence_disabled(self) -> bool:
+        return self.is_zephyr_mirror_realm
+
+    def web_public_streams_enabled(self) -> bool:
+        if not settings.WEB_PUBLIC_STREAMS_ENABLED:
+            # To help protect against accidentally web-public streams in
+            # self-hosted servers, we require the feature to be enabled at
+            # the server level before it is available to users.
+            return False
+
+        if self.plan_type == Realm.PLAN_TYPE_LIMITED:
+            # In Zulip Cloud, we also require a paid or sponsored
+            # plan, to protect against the spam/abuse attacks that
+            # target every open Internet service that can host files.
+            return False
+
+        if not self.enable_spectator_access:
+            return False
+
+        return True
+
+    def has_web_public_streams(self) -> bool:
+        if not self.web_public_streams_enabled():
+            return False
+
+        from zerver.lib.streams import get_web_public_streams_queryset
+
+        return get_web_public_streams_queryset(self).exists()
+
+    def allow_web_public_streams_access(self) -> bool:
+        """
+        If any of the streams in the realm is web
+        public and `enable_spectator_access` and
+        settings.WEB_PUBLIC_STREAMS_ENABLED is True,
+        then the Realm is web-public.
+        """
+        return self.has_web_public_streams()
+
+
+post_save.connect(flush_realm, sender=Realm)
+
+
+# We register realm cache flushing in a duplicate way to be run both
+# pre_delete and post_delete on purpose:
+# 1. pre_delete is needed because flush_realm wants to flush the UserProfile caches,
+#    and UserProfile objects are deleted via on_delete=CASCADE before the post_delete handler
+#    is called, which results in the `flush_realm` logic not having access to the details
+#    for the deleted users if called at that time.
+# 2. post_delete is run as a precaution to reduce the risk of races where items might be
+#    added to the cache after the pre_delete handler but before the save.
+#    Note that it does not eliminate this risk, not least because it only flushes
+#    the realm cache, and not the user caches, for the reasons explained above.
+def realm_pre_and_post_delete_handler(*, instance: Realm, **kwargs: object) -> None:
+    # This would be better as a functools.partial, but for some reason
+    # Django doesn't call it even when it's registered as a post_delete handler.
+    flush_realm(instance=instance, from_deletion=True)
+
+
+pre_delete.connect(realm_pre_and_post_delete_handler, sender=Realm)
+post_delete.connect(realm_pre_and_post_delete_handler, sender=Realm)
+
+
+def get_realm(string_id: str) -> Realm:
+    return Realm.objects.get(string_id=string_id)
+
+
+def get_realm_by_id(realm_id: int) -> Realm:
+    return Realm.objects.get(id=realm_id)
+
+
+def name_changes_disabled(realm: Optional[Realm]) -> bool:
+    if realm is None:
+        return settings.NAME_CHANGES_DISABLED
+    return settings.NAME_CHANGES_DISABLED or realm.name_changes_disabled
+
+
+def avatar_changes_disabled(realm: Realm) -> bool:
+    return settings.AVATAR_CHANGES_DISABLED or realm.avatar_changes_disabled
+
+
+def get_org_type_display_name(org_type: int) -> str:
+    for realm_type_details in Realm.ORG_TYPES.values():
+        if realm_type_details["id"] == org_type:
+            return realm_type_details["name"]
+
+    return ""
+
+
+class RealmDomain(models.Model):
+    """For an organization with emails_restricted_to_domains enabled, the list of
+    allowed domains"""
+
+    realm = models.ForeignKey(Realm, on_delete=CASCADE)
+    # should always be stored lowercase
+    domain = models.CharField(max_length=80, db_index=True)
+    allow_subdomains = models.BooleanField(default=False)
+
+    class Meta:
+        unique_together = ("realm", "domain")
+
+
+class DomainNotAllowedForRealmError(Exception):
+    pass
+
+
+class DisposableEmailError(Exception):
+    pass
+
+
+class EmailContainsPlusError(Exception):
+    pass
+
+
+class RealmDomainDict(TypedDict):
+    domain: str
+    allow_subdomains: bool
+
+
+def get_realm_domains(realm: Realm) -> List[RealmDomainDict]:
+    return list(realm.realmdomain_set.values("domain", "allow_subdomains"))
+
+
+class InvalidFakeEmailDomainError(Exception):
+    pass
+
+
+def get_fake_email_domain(realm_host: str) -> str:
+    try:
+        # Check that realm.host can be used to form valid email addresses.
+        validate_email(Address(username="bot", domain=realm_host).addr_spec)
+        return realm_host
+    except ValidationError:
+        pass
+
+    try:
+        # Check that the fake email domain can be used to form valid email addresses.
+        validate_email(Address(username="bot", domain=settings.FAKE_EMAIL_DOMAIN).addr_spec)
+    except ValidationError:
+        raise InvalidFakeEmailDomainError(
+            settings.FAKE_EMAIL_DOMAIN + " is not a valid domain. "
+            "Consider setting the FAKE_EMAIL_DOMAIN setting."
+        )
+
+    return settings.FAKE_EMAIL_DOMAIN
diff --git a/zerver/models/users.py b/zerver/models/users.py
index bfb74787d3..26d7b5f93e 100644
--- a/zerver/models/users.py
+++ b/zerver/models/users.py
@@ -1060,7 +1060,8 @@ def bot_owner_user_ids(user_profile: UserProfile) -> Set[int]:
 
 
 def get_source_profile(email: str, realm_id: int) -> Optional[UserProfile]:
-    from zerver.models import Realm, get_realm_by_id
+    from zerver.models import Realm
+    from zerver.models.realms import get_realm_by_id
 
     try:
         return get_user_by_delivery_email(email, get_realm_by_id(realm_id))
diff --git a/zerver/openapi/curl_param_value_generators.py b/zerver/openapi/curl_param_value_generators.py
index 58e56d90c3..3b7efb859b 100644
--- a/zerver/openapi/curl_param_value_generators.py
+++ b/zerver/openapi/curl_param_value_generators.py
@@ -20,7 +20,8 @@ from zerver.lib.initial_password import initial_password
 from zerver.lib.test_classes import ZulipTestCase
 from zerver.lib.upload import upload_message_attachment
 from zerver.lib.users import get_api_key
-from zerver.models import Client, Message, UserGroup, UserPresence, get_realm
+from zerver.models import Client, Message, UserGroup, UserPresence
+from zerver.models.realms import get_realm
 from zerver.models.users import get_user
 
 GENERATOR_FUNCTIONS: Dict[str, Callable[[], Dict[str, object]]] = {}
diff --git a/zerver/openapi/python_examples.py b/zerver/openapi/python_examples.py
index 2a1c6f4076..1cb811951f 100644
--- a/zerver/openapi/python_examples.py
+++ b/zerver/openapi/python_examples.py
@@ -22,7 +22,7 @@ from typing import Any, Callable, Dict, List, Set, TypeVar
 from typing_extensions import ParamSpec
 from zulip import Client
 
-from zerver.models import get_realm
+from zerver.models.realms import get_realm
 from zerver.models.users import get_user
 from zerver.openapi.openapi import validate_against_openapi_schema
 
diff --git a/zerver/openapi/test_curl_examples.py b/zerver/openapi/test_curl_examples.py
index f487cfc972..b009afb198 100644
--- a/zerver/openapi/test_curl_examples.py
+++ b/zerver/openapi/test_curl_examples.py
@@ -16,7 +16,7 @@ import markdown
 from django.conf import settings
 from zulip import Client
 
-from zerver.models import get_realm
+from zerver.models.realms import get_realm
 from zerver.openapi import markdown_extension
 from zerver.openapi.curl_param_value_generators import (
     AUTHENTICATION_LINE,
diff --git a/zerver/tests/test_audit_log.py b/zerver/tests/test_audit_log.py
index 52a5217a75..6e601775e7 100644
--- a/zerver/tests/test_audit_log.py
+++ b/zerver/tests/test_audit_log.py
@@ -77,20 +77,18 @@ from zerver.models import (
     Message,
     Realm,
     RealmAuditLog,
-    RealmDomainDict,
     RealmPlayground,
     Recipient,
     Subscription,
     UserGroup,
     UserProfile,
     get_all_custom_emoji_for_realm,
-    get_realm,
-    get_realm_domains,
     get_realm_playgrounds,
     get_stream,
     linkifiers_for_realm,
 )
 from zerver.models.groups import SystemGroups
+from zerver.models.realms import RealmDomainDict, get_realm, get_realm_domains
 
 
 class TestRealmAuditLog(ZulipTestCase):
diff --git a/zerver/tests/test_auth_backends.py b/zerver/tests/test_auth_backends.py
index f91ff9fcba..4d5bb2be96 100644
--- a/zerver/tests/test_auth_backends.py
+++ b/zerver/tests/test_auth_backends.py
@@ -116,9 +116,8 @@ from zerver.models import (
     Stream,
     UserGroup,
     UserProfile,
-    clear_supported_auth_backends_cache,
-    get_realm,
 )
+from zerver.models.realms import clear_supported_auth_backends_cache, get_realm
 from zerver.models.users import PasswordTooWeakError, get_user_by_delivery_email
 from zerver.signals import JUST_CREATED_THRESHOLD
 from zerver.views.auth import log_into_subdomain, maybe_send_to_registration
diff --git a/zerver/tests/test_bots.py b/zerver/tests/test_bots.py
index 5567b76644..4aecbf1f07 100644
--- a/zerver/tests/test_bots.py
+++ b/zerver/tests/test_bots.py
@@ -24,9 +24,9 @@ from zerver.models import (
     Subscription,
     UserProfile,
     get_bot_services,
-    get_realm,
     get_stream,
 )
+from zerver.models.realms import get_realm
 from zerver.models.users import get_user, is_cross_realm_bot_email
 
 
diff --git a/zerver/tests/test_cache.py b/zerver/tests/test_cache.py
index b7f75bf7ef..5f0730dff5 100644
--- a/zerver/tests/test_cache.py
+++ b/zerver/tests/test_cache.py
@@ -21,7 +21,8 @@ from zerver.lib.cache import (
     validate_cache_key,
 )
 from zerver.lib.test_classes import ZulipTestCase
-from zerver.models import UserProfile, get_realm
+from zerver.models import UserProfile
+from zerver.models.realms import get_realm
 from zerver.models.users import get_system_bot, get_user, get_user_profile_by_id
 
 
diff --git a/zerver/tests/test_custom_profile_data.py b/zerver/tests/test_custom_profile_data.py
index 39a8f88eea..e83d026015 100644
--- a/zerver/tests/test_custom_profile_data.py
+++ b/zerver/tests/test_custom_profile_data.py
@@ -20,8 +20,8 @@ from zerver.models import (
     CustomProfileFieldValue,
     UserProfile,
     custom_profile_fields_for_realm,
-    get_realm,
 )
+from zerver.models.realms import get_realm
 
 
 class CustomProfileFieldTestCase(ZulipTestCase):
diff --git a/zerver/tests/test_decorators.py b/zerver/tests/test_decorators.py
index 4914d7121c..02dd5b62be 100644
--- a/zerver/tests/test_decorators.py
+++ b/zerver/tests/test_decorators.py
@@ -52,7 +52,8 @@ from zerver.lib.user_agent import parse_user_agent
 from zerver.lib.users import get_api_key
 from zerver.lib.utils import generate_api_key, has_api_key_format
 from zerver.middleware import LogRequests, parse_client
-from zerver.models import Client, Realm, UserProfile, clear_client_cache, get_realm
+from zerver.models import Client, Realm, UserProfile, clear_client_cache
+from zerver.models.realms import get_realm
 from zerver.models.users import get_user
 
 if settings.ZILENCER_ENABLED:
diff --git a/zerver/tests/test_digest.py b/zerver/tests/test_digest.py
index 5c2eb3e498..a8da00bc6c 100644
--- a/zerver/tests/test_digest.py
+++ b/zerver/tests/test_digest.py
@@ -33,9 +33,9 @@ from zerver.models import (
     Stream,
     UserActivityInterval,
     UserProfile,
-    get_realm,
     get_stream,
 )
+from zerver.models.realms import get_realm
 
 
 class TestDigestEmailMessages(ZulipTestCase):
diff --git a/zerver/tests/test_docs.py b/zerver/tests/test_docs.py
index ab8770d4b3..b34b268112 100644
--- a/zerver/tests/test_docs.py
+++ b/zerver/tests/test_docs.py
@@ -14,7 +14,8 @@ from zerver.context_processors import get_apps_page_url
 from zerver.lib.integrations import CATEGORIES, INTEGRATIONS, META_CATEGORY
 from zerver.lib.test_classes import ZulipTestCase
 from zerver.lib.test_helpers import HostRequestMock
-from zerver.models import Realm, get_realm
+from zerver.models import Realm
+from zerver.models.realms import get_realm
 from zerver.views.documentation import add_api_url_context
 
 if TYPE_CHECKING:
diff --git a/zerver/tests/test_email_change.py b/zerver/tests/test_email_change.py
index 0d8f7b61c7..65009f30f7 100644
--- a/zerver/tests/test_email_change.py
+++ b/zerver/tests/test_email_change.py
@@ -18,7 +18,8 @@ from zerver.actions.realm_settings import do_deactivate_realm, do_set_realm_prop
 from zerver.actions.user_settings import do_change_user_setting, do_start_email_change_process
 from zerver.actions.users import do_deactivate_user
 from zerver.lib.test_classes import ZulipTestCase
-from zerver.models import EmailChangeStatus, UserProfile, get_realm
+from zerver.models import EmailChangeStatus, UserProfile
+from zerver.models.realms import get_realm
 from zerver.models.users import get_user, get_user_by_delivery_email, get_user_profile_by_id
 
 
diff --git a/zerver/tests/test_email_mirror.py b/zerver/tests/test_email_mirror.py
index eea87920cd..425c5478a6 100644
--- a/zerver/tests/test_email_mirror.py
+++ b/zerver/tests/test_email_mirror.py
@@ -37,7 +37,8 @@ from zerver.lib.send_email import FromAddress
 from zerver.lib.streams import ensure_stream
 from zerver.lib.test_classes import ZulipTestCase
 from zerver.lib.test_helpers import mock_queue_publish, most_recent_message, most_recent_usermessage
-from zerver.models import Attachment, Recipient, Stream, UserProfile, get_realm, get_stream
+from zerver.models import Attachment, Recipient, Stream, UserProfile, get_stream
+from zerver.models.realms import get_realm
 from zerver.models.users import get_system_bot
 from zerver.worker.queue_processors import MirrorWorker
 
diff --git a/zerver/tests/test_email_notifications.py b/zerver/tests/test_email_notifications.py
index 3fa46e4540..d2b3b82d42 100644
--- a/zerver/tests/test_email_notifications.py
+++ b/zerver/tests/test_email_notifications.py
@@ -22,7 +22,8 @@ from zerver.lib.send_email import (
     send_custom_server_email,
 )
 from zerver.lib.test_classes import ZulipTestCase
-from zerver.models import Realm, ScheduledEmail, UserProfile, get_realm
+from zerver.models import Realm, ScheduledEmail, UserProfile
+from zerver.models.realms import get_realm
 from zilencer.models import RemoteZulipServer
 
 
diff --git a/zerver/tests/test_embedded_bot_system.py b/zerver/tests/test_embedded_bot_system.py
index bd52d952df..bca7c86bc6 100644
--- a/zerver/tests/test_embedded_bot_system.py
+++ b/zerver/tests/test_embedded_bot_system.py
@@ -5,7 +5,8 @@ from typing_extensions import override
 
 from zerver.lib.bot_lib import EmbeddedBotQuitError
 from zerver.lib.test_classes import ZulipTestCase
-from zerver.models import UserProfile, get_display_recipient, get_realm, get_service_profile
+from zerver.models import UserProfile, get_display_recipient, get_service_profile
+from zerver.models.realms import get_realm
 from zerver.models.users import get_user
 
 
diff --git a/zerver/tests/test_event_system.py b/zerver/tests/test_event_system.py
index 0b316d679a..0513a5105a 100644
--- a/zerver/tests/test_event_system.py
+++ b/zerver/tests/test_event_system.py
@@ -34,9 +34,9 @@ from zerver.models import (
     UserPresence,
     UserProfile,
     get_client,
-    get_realm,
     get_stream,
 )
+from zerver.models.realms import get_realm
 from zerver.models.users import get_system_bot
 from zerver.tornado.event_queue import (
     allocate_client_descriptor,
diff --git a/zerver/tests/test_example.py b/zerver/tests/test_example.py
index 4be0e57a84..8ae9d79e86 100644
--- a/zerver/tests/test_example.py
+++ b/zerver/tests/test_example.py
@@ -11,7 +11,8 @@ from zerver.lib.streams import access_stream_for_send_message
 from zerver.lib.test_classes import ZulipTestCase
 from zerver.lib.test_helpers import most_recent_message
 from zerver.lib.users import is_administrator_role
-from zerver.models import UserProfile, UserStatus, get_realm, get_stream
+from zerver.models import UserProfile, UserStatus, get_stream
+from zerver.models.realms import get_realm
 from zerver.models.users import get_user_by_delivery_email
 
 
diff --git a/zerver/tests/test_gitter_importer.py b/zerver/tests/test_gitter_importer.py
index 5a8502b9c3..75e950acbd 100644
--- a/zerver/tests/test_gitter_importer.py
+++ b/zerver/tests/test_gitter_importer.py
@@ -10,7 +10,8 @@ import time_machine
 from zerver.data_import.gitter import do_convert_data, get_usermentions
 from zerver.lib.import_realm import do_import_realm
 from zerver.lib.test_classes import ZulipTestCase
-from zerver.models import Message, UserProfile, get_realm
+from zerver.models import Message, UserProfile
+from zerver.models.realms import get_realm
 from zproject.backends import (
     AUTH_BACKEND_NAME_MAP,
     GitHubAuthBackend,
diff --git a/zerver/tests/test_home.py b/zerver/tests/test_home.py
index 4a00c1b7de..29ff92b6b1 100644
--- a/zerver/tests/test_home.py
+++ b/zerver/tests/test_home.py
@@ -24,15 +24,8 @@ from zerver.lib.soft_deactivation import do_soft_deactivate_users
 from zerver.lib.test_classes import ZulipTestCase
 from zerver.lib.test_helpers import get_user_messages, queries_captured
 from zerver.lib.timestamp import datetime_to_timestamp
-from zerver.models import (
-    DefaultStream,
-    Draft,
-    Realm,
-    UserActivity,
-    UserProfile,
-    get_realm,
-    get_stream,
-)
+from zerver.models import DefaultStream, Draft, Realm, UserActivity, UserProfile, get_stream
+from zerver.models.realms import get_realm
 from zerver.models.users import get_system_bot, get_user
 from zerver.worker.queue_processors import UserActivityWorker
 
diff --git a/zerver/tests/test_hotspots.py b/zerver/tests/test_hotspots.py
index 8c12554d28..766b49b5d2 100644
--- a/zerver/tests/test_hotspots.py
+++ b/zerver/tests/test_hotspots.py
@@ -10,7 +10,8 @@ from zerver.lib.hotspots import (
     get_next_onboarding_steps,
 )
 from zerver.lib.test_classes import ZulipTestCase
-from zerver.models import OnboardingStep, UserProfile, get_realm
+from zerver.models import OnboardingStep, UserProfile
+from zerver.models.realms import get_realm
 
 
 # Splitting this out, since I imagine this will eventually have most of the
diff --git a/zerver/tests/test_import_export.py b/zerver/tests/test_import_export.py
index 4d32e1b911..c0b6a00c3f 100644
--- a/zerver/tests/test_import_export.py
+++ b/zerver/tests/test_import_export.py
@@ -86,10 +86,10 @@ from zerver.models import (
     get_active_streams,
     get_client,
     get_huddle_hash,
-    get_realm,
     get_stream,
 )
 from zerver.models.groups import SystemGroups
+from zerver.models.realms import get_realm
 from zerver.models.users import get_system_bot, get_user_by_delivery_email
 
 
diff --git a/zerver/tests/test_integrations_dev_panel.py b/zerver/tests/test_integrations_dev_panel.py
index 5fd7d70858..0b2b17b829 100644
--- a/zerver/tests/test_integrations_dev_panel.py
+++ b/zerver/tests/test_integrations_dev_panel.py
@@ -4,7 +4,8 @@ import orjson
 from django.core.exceptions import ValidationError
 
 from zerver.lib.test_classes import ZulipTestCase
-from zerver.models import Message, Stream, get_realm
+from zerver.models import Message, Stream
+from zerver.models.realms import get_realm
 from zerver.models.users import get_user
 
 
diff --git a/zerver/tests/test_invite.py b/zerver/tests/test_invite.py
index 77595c1b80..2e17f75d57 100644
--- a/zerver/tests/test_invite.py
+++ b/zerver/tests/test_invite.py
@@ -63,10 +63,10 @@ from zerver.models import (
     UserGroup,
     UserMessage,
     UserProfile,
-    get_realm,
     get_stream,
 )
 from zerver.models.groups import SystemGroups
+from zerver.models.realms import get_realm
 from zerver.models.users import get_user_by_delivery_email
 from zerver.views.invite import INVITATION_LINK_VALIDITY_MINUTES, get_invitee_emails_set
 from zerver.views.registration import accounts_home
diff --git a/zerver/tests/test_management_commands.py b/zerver/tests/test_management_commands.py
index 2391ec7aed..975e8eb24c 100644
--- a/zerver/tests/test_management_commands.py
+++ b/zerver/tests/test_management_commands.py
@@ -20,7 +20,8 @@ from zerver.actions.reactions import do_add_reaction
 from zerver.lib.management import ZulipBaseCommand, check_config
 from zerver.lib.test_classes import ZulipTestCase
 from zerver.lib.test_helpers import most_recent_message, stdout_suppressed
-from zerver.models import Message, Reaction, Realm, Recipient, UserProfile, get_realm, get_stream
+from zerver.models import Message, Reaction, Realm, Recipient, UserProfile, get_stream
+from zerver.models.realms import get_realm
 from zerver.models.users import get_user_profile_by_email
 
 
diff --git a/zerver/tests/test_markdown.py b/zerver/tests/test_markdown.py
index 514f328637..d82d6ff535 100644
--- a/zerver/tests/test_markdown.py
+++ b/zerver/tests/test_markdown.py
@@ -68,11 +68,11 @@ from zerver.models import (
     UserMessage,
     UserProfile,
     get_client,
-    get_realm,
     get_stream,
     linkifiers_for_realm,
 )
 from zerver.models.groups import SystemGroups
+from zerver.models.realms import get_realm
 
 
 class SimulatedFencedBlockPreprocessor(FencedBlockPreprocessor):
diff --git a/zerver/tests/test_mattermost_importer.py b/zerver/tests/test_mattermost_importer.py
index 281a668f86..d7251e1385 100644
--- a/zerver/tests/test_mattermost_importer.py
+++ b/zerver/tests/test_mattermost_importer.py
@@ -28,7 +28,8 @@ from zerver.data_import.user_handler import UserHandler
 from zerver.lib.emoji import name_to_codepoint
 from zerver.lib.import_realm import do_import_realm
 from zerver.lib.test_classes import ZulipTestCase
-from zerver.models import Message, Reaction, Recipient, UserProfile, get_realm
+from zerver.models import Message, Reaction, Recipient, UserProfile
+from zerver.models.realms import get_realm
 from zerver.models.users import get_user
 
 
diff --git a/zerver/tests/test_message_dict.py b/zerver/tests/test_message_dict.py
index 291af89b79..c3da52d7d8 100644
--- a/zerver/tests/test_message_dict.py
+++ b/zerver/tests/test_message_dict.py
@@ -20,9 +20,9 @@ from zerver.models import (
     Stream,
     UserProfile,
     get_display_recipient,
-    get_realm,
     get_stream,
 )
+from zerver.models.realms import get_realm
 
 
 class MessageDictTest(ZulipTestCase):
diff --git a/zerver/tests/test_message_edit.py b/zerver/tests/test_message_edit.py
index a23f6d7a2e..16fa688c30 100644
--- a/zerver/tests/test_message_edit.py
+++ b/zerver/tests/test_message_edit.py
@@ -38,11 +38,11 @@ from zerver.models import (
     UserMessage,
     UserProfile,
     UserTopic,
-    get_realm,
     get_stream,
 )
 from zerver.models.constants import MAX_TOPIC_NAME_LENGTH
 from zerver.models.groups import SystemGroups
+from zerver.models.realms import get_realm
 
 if TYPE_CHECKING:
     from django.test.client import _MonkeyPatchedWSGIResponse as TestHttpResponse
diff --git a/zerver/tests/test_message_fetch.py b/zerver/tests/test_message_fetch.py
index a4391638c0..801d23b7f4 100644
--- a/zerver/tests/test_message_fetch.py
+++ b/zerver/tests/test_message_fetch.py
@@ -58,9 +58,9 @@ from zerver.models import (
     UserProfile,
     UserTopic,
     get_display_recipient,
-    get_realm,
     get_stream,
 )
+from zerver.models.realms import get_realm
 from zerver.views.message_fetch import get_messages_backend
 
 if TYPE_CHECKING:
diff --git a/zerver/tests/test_message_flags.py b/zerver/tests/test_message_flags.py
index abb5c04436..be1082be0a 100644
--- a/zerver/tests/test_message_flags.py
+++ b/zerver/tests/test_message_flags.py
@@ -33,9 +33,9 @@ from zerver.models import (
     UserMessage,
     UserProfile,
     UserTopic,
-    get_realm,
     get_stream,
 )
+from zerver.models.realms import get_realm
 
 if TYPE_CHECKING:
     from django.test.client import _MonkeyPatchedWSGIResponse as TestHttpResponse
diff --git a/zerver/tests/test_message_notification_emails.py b/zerver/tests/test_message_notification_emails.py
index ac3fda6d6a..c734219bbf 100644
--- a/zerver/tests/test_message_notification_emails.py
+++ b/zerver/tests/test_message_notification_emails.py
@@ -33,9 +33,9 @@ from zerver.models import (
     UserProfile,
     UserTopic,
     get_name_keyed_dict_for_active_realm_emoji,
-    get_realm,
     get_stream,
 )
+from zerver.models.realms import get_realm
 
 
 class TestMessageNotificationEmails(ZulipTestCase):
diff --git a/zerver/tests/test_message_send.py b/zerver/tests/test_message_send.py
index a523922005..b8b268c0b9 100644
--- a/zerver/tests/test_message_send.py
+++ b/zerver/tests/test_message_send.py
@@ -57,11 +57,11 @@ from zerver.models import (
     UserMessage,
     UserProfile,
     get_or_create_huddle,
-    get_realm,
     get_stream,
 )
 from zerver.models.constants import MAX_TOPIC_NAME_LENGTH
 from zerver.models.groups import SystemGroups
+from zerver.models.realms import get_realm
 from zerver.models.users import get_system_bot, get_user
 from zerver.views.message_send import InvalidMirrorInputError
 
diff --git a/zerver/tests/test_message_topics.py b/zerver/tests/test_message_topics.py
index ec65b21d28..a0b72b2d22 100644
--- a/zerver/tests/test_message_topics.py
+++ b/zerver/tests/test_message_topics.py
@@ -6,7 +6,8 @@ from zerver.actions.streams import do_change_stream_permission
 from zerver.lib.test_classes import ZulipTestCase
 from zerver.lib.test_helpers import timeout_mock
 from zerver.lib.timeout import TimeoutExpiredError
-from zerver.models import Message, UserMessage, get_client, get_realm, get_stream
+from zerver.models import Message, UserMessage, get_client, get_stream
+from zerver.models.realms import get_realm
 
 
 class TopicHistoryTest(ZulipTestCase):
diff --git a/zerver/tests/test_middleware.py b/zerver/tests/test_middleware.py
index 6182ba3806..e701719b68 100644
--- a/zerver/tests/test_middleware.py
+++ b/zerver/tests/test_middleware.py
@@ -11,7 +11,7 @@ from zerver.lib.test_classes import ZulipTestCase
 from zerver.lib.test_helpers import HostRequestMock
 from zerver.lib.utils import assert_is_not_none
 from zerver.middleware import LogRequests, is_slow_query, write_log_line
-from zerver.models import get_realm
+from zerver.models.realms import get_realm
 from zilencer.models import RemoteZulipServer
 
 
diff --git a/zerver/tests/test_mirror_users.py b/zerver/tests/test_mirror_users.py
index 24464d1e1b..133521f646 100644
--- a/zerver/tests/test_mirror_users.py
+++ b/zerver/tests/test_mirror_users.py
@@ -8,7 +8,8 @@ from zerver.actions.message_send import create_mirror_user_if_needed
 from zerver.lib.create_user import create_user_profile
 from zerver.lib.test_classes import ZulipTestCase
 from zerver.lib.test_helpers import reset_email_visibility_to_everyone_in_zulip_realm
-from zerver.models import UserProfile, get_client, get_realm
+from zerver.models import UserProfile, get_client
+from zerver.models.realms import get_realm
 from zerver.models.users import get_user
 from zerver.views.message_send import InvalidMirrorInputError, create_mirrored_message_users
 
diff --git a/zerver/tests/test_new_users.py b/zerver/tests/test_new_users.py
index cb2e392fc2..14e90cf88e 100644
--- a/zerver/tests/test_new_users.py
+++ b/zerver/tests/test_new_users.py
@@ -13,7 +13,8 @@ from zerver.actions.create_user import notify_new_user
 from zerver.actions.user_settings import do_change_user_setting
 from zerver.lib.initial_password import initial_password
 from zerver.lib.test_classes import ZulipTestCase
-from zerver.models import Message, Realm, Recipient, Stream, UserProfile, get_realm
+from zerver.models import Message, Realm, Recipient, Stream, UserProfile
+from zerver.models.realms import get_realm
 from zerver.signals import JUST_CREATED_THRESHOLD, get_device_browser, get_device_os
 
 if sys.version_info < (3, 9):  # nocoverage
diff --git a/zerver/tests/test_outgoing_webhook_interfaces.py b/zerver/tests/test_outgoing_webhook_interfaces.py
index f66510cb0f..57ff699fef 100644
--- a/zerver/tests/test_outgoing_webhook_interfaces.py
+++ b/zerver/tests/test_outgoing_webhook_interfaces.py
@@ -12,7 +12,8 @@ from zerver.lib.outgoing_webhook import get_service_interface_class, process_suc
 from zerver.lib.test_classes import ZulipTestCase
 from zerver.lib.timestamp import datetime_to_timestamp
 from zerver.lib.topic import TOPIC_NAME
-from zerver.models import SLACK_INTERFACE, Message, NotificationTriggers, get_realm, get_stream
+from zerver.models import SLACK_INTERFACE, Message, NotificationTriggers, get_stream
+from zerver.models.realms import get_realm
 from zerver.models.users import get_user
 from zerver.openapi.openapi import validate_against_openapi_schema
 
diff --git a/zerver/tests/test_outgoing_webhook_system.py b/zerver/tests/test_outgoing_webhook_system.py
index cda83d5ff3..f6dad2df96 100644
--- a/zerver/tests/test_outgoing_webhook_system.py
+++ b/zerver/tests/test_outgoing_webhook_system.py
@@ -19,7 +19,8 @@ from zerver.lib.test_classes import ZulipTestCase
 from zerver.lib.topic import TOPIC_NAME
 from zerver.lib.url_encoding import near_message_url
 from zerver.lib.users import add_service
-from zerver.models import Recipient, Service, UserProfile, get_realm, get_stream
+from zerver.models import Recipient, Service, UserProfile, get_stream
+from zerver.models.realms import get_realm
 
 
 class ResponseMock:
diff --git a/zerver/tests/test_presence.py b/zerver/tests/test_presence.py
index cfbee31d56..84a63328f2 100644
--- a/zerver/tests/test_presence.py
+++ b/zerver/tests/test_presence.py
@@ -18,8 +18,8 @@ from zerver.models import (
     UserActivityInterval,
     UserPresence,
     UserProfile,
-    get_realm,
 )
+from zerver.models.realms import get_realm
 
 
 class TestClientModel(ZulipTestCase):
diff --git a/zerver/tests/test_push_notifications.py b/zerver/tests/test_push_notifications.py
index 0441d988f0..27a7ddbb3d 100644
--- a/zerver/tests/test_push_notifications.py
+++ b/zerver/tests/test_push_notifications.py
@@ -91,9 +91,9 @@ from zerver.models import (
     UserProfile,
     UserTopic,
     get_client,
-    get_realm,
     get_stream,
 )
+from zerver.models.realms import get_realm
 from zilencer.models import RemoteZulipServerAuditLog
 from zilencer.views import DevicesToCleanUpDict
 
diff --git a/zerver/tests/test_queue_worker.py b/zerver/tests/test_queue_worker.py
index c0a90309d2..452fbca45c 100644
--- a/zerver/tests/test_queue_worker.py
+++ b/zerver/tests/test_queue_worker.py
@@ -32,9 +32,9 @@ from zerver.models import (
     UserActivity,
     UserProfile,
     get_client,
-    get_realm,
     get_stream,
 )
+from zerver.models.realms import get_realm
 from zerver.tornado.event_queue import build_offline_notification
 from zerver.worker import queue_processors
 from zerver.worker.queue_processors import (
diff --git a/zerver/tests/test_reactions.py b/zerver/tests/test_reactions.py
index b015896e04..fdd94adc21 100644
--- a/zerver/tests/test_reactions.py
+++ b/zerver/tests/test_reactions.py
@@ -12,7 +12,8 @@ from zerver.lib.exceptions import JsonableError
 from zerver.lib.message import extract_message_dict
 from zerver.lib.test_classes import ZulipTestCase
 from zerver.lib.test_helpers import zulip_reaction_info
-from zerver.models import Message, Reaction, RealmEmoji, UserMessage, get_realm
+from zerver.models import Message, Reaction, RealmEmoji, UserMessage
+from zerver.models.realms import get_realm
 
 if TYPE_CHECKING:
     from django.test.client import _MonkeyPatchedWSGIResponse as TestHttpResponse
diff --git a/zerver/tests/test_realm.py b/zerver/tests/test_realm.py
index 837f5d4fa0..a2fdbf446e 100644
--- a/zerver/tests/test_realm.py
+++ b/zerver/tests/test_realm.py
@@ -53,10 +53,10 @@ from zerver.models import (
     UserGroupMembership,
     UserMessage,
     UserProfile,
-    get_realm,
     get_stream,
 )
 from zerver.models.groups import SystemGroups
+from zerver.models.realms import get_realm
 from zerver.models.users import get_system_bot, get_user_profile_by_id
 
 
diff --git a/zerver/tests/test_realm_domains.py b/zerver/tests/test_realm_domains.py
index 9faacd31ec..e78b62048a 100644
--- a/zerver/tests/test_realm_domains.py
+++ b/zerver/tests/test_realm_domains.py
@@ -10,7 +10,8 @@ from zerver.actions.users import do_change_user_role
 from zerver.lib.domains import validate_domain
 from zerver.lib.email_validation import email_allowed_for_realm
 from zerver.lib.test_classes import ZulipTestCase
-from zerver.models import DomainNotAllowedForRealmError, RealmDomain, UserProfile, get_realm
+from zerver.models import RealmDomain, UserProfile
+from zerver.models.realms import DomainNotAllowedForRealmError, get_realm
 
 
 class RealmDomainTest(ZulipTestCase):
diff --git a/zerver/tests/test_realm_emoji.py b/zerver/tests/test_realm_emoji.py
index 28c5921729..603caa3723 100644
--- a/zerver/tests/test_realm_emoji.py
+++ b/zerver/tests/test_realm_emoji.py
@@ -9,7 +9,8 @@ from zerver.lib.exceptions import JsonableError
 from zerver.lib.test_classes import ZulipTestCase
 from zerver.lib.test_helpers import get_test_image_file
 from zerver.lib.upload.base import BadImageError
-from zerver.models import Realm, RealmEmoji, UserProfile, get_realm
+from zerver.models import Realm, RealmEmoji, UserProfile
+from zerver.models.realms import get_realm
 
 
 class RealmEmojiTest(ZulipTestCase):
diff --git a/zerver/tests/test_realm_playgrounds.py b/zerver/tests/test_realm_playgrounds.py
index 97ac4fe43e..45e23b8de1 100644
--- a/zerver/tests/test_realm_playgrounds.py
+++ b/zerver/tests/test_realm_playgrounds.py
@@ -1,6 +1,7 @@
 from zerver.actions.realm_playgrounds import check_add_realm_playground
 from zerver.lib.test_classes import ZulipTestCase
-from zerver.models import RealmPlayground, get_realm
+from zerver.models import RealmPlayground
+from zerver.models.realms import get_realm
 
 
 class RealmPlaygroundTests(ZulipTestCase):
diff --git a/zerver/tests/test_retention.py b/zerver/tests/test_retention.py
index 340fee5689..55d8b7dbcc 100644
--- a/zerver/tests/test_retention.py
+++ b/zerver/tests/test_retention.py
@@ -38,9 +38,9 @@ from zerver.models import (
     SubMessage,
     UserMessage,
     get_client,
-    get_realm,
     get_stream,
 )
+from zerver.models.realms import get_realm
 from zerver.models.users import get_system_bot
 
 # Class with helper functions useful for testing archiving of reactions:
diff --git a/zerver/tests/test_rocketchat_importer.py b/zerver/tests/test_rocketchat_importer.py
index bc2b98bb15..f11533b5d2 100644
--- a/zerver/tests/test_rocketchat_importer.py
+++ b/zerver/tests/test_rocketchat_importer.py
@@ -28,7 +28,8 @@ from zerver.data_import.user_handler import UserHandler
 from zerver.lib.emoji import name_to_codepoint
 from zerver.lib.import_realm import do_import_realm
 from zerver.lib.test_classes import ZulipTestCase
-from zerver.models import Message, Reaction, Recipient, UserProfile, get_realm
+from zerver.models import Message, Reaction, Recipient, UserProfile
+from zerver.models.realms import get_realm
 from zerver.models.users import get_user
 
 
diff --git a/zerver/tests/test_scim.py b/zerver/tests/test_scim.py
index 1bab9984d4..600c191de5 100644
--- a/zerver/tests/test_scim.py
+++ b/zerver/tests/test_scim.py
@@ -10,7 +10,8 @@ from typing_extensions import override
 from zerver.actions.user_settings import do_change_full_name
 from zerver.lib.scim import ZulipSCIMUser
 from zerver.lib.test_classes import ZulipTestCase
-from zerver.models import UserProfile, get_realm
+from zerver.models import UserProfile
+from zerver.models.realms import get_realm
 
 if TYPE_CHECKING:
     from django.test.client import _MonkeyPatchedWSGIResponse as TestHttpResponse
diff --git a/zerver/tests/test_service_bot_system.py b/zerver/tests/test_service_bot_system.py
index 5eda173fbc..131b30d803 100644
--- a/zerver/tests/test_service_bot_system.py
+++ b/zerver/tests/test_service_bot_system.py
@@ -15,7 +15,8 @@ from zerver.lib.bot_storage import StateError
 from zerver.lib.test_classes import ZulipTestCase
 from zerver.lib.test_helpers import mock_queue_publish
 from zerver.lib.validator import check_string
-from zerver.models import NotificationTriggers, Recipient, UserProfile, get_realm
+from zerver.models import NotificationTriggers, Recipient, UserProfile
+from zerver.models.realms import get_realm
 
 BOT_TYPE_TO_QUEUE_NAME = {
     UserProfile.OUTGOING_WEBHOOK_BOT: "outgoing_webhooks",
diff --git a/zerver/tests/test_sessions.py b/zerver/tests/test_sessions.py
index ccebe1980f..1d77a28a27 100644
--- a/zerver/tests/test_sessions.py
+++ b/zerver/tests/test_sessions.py
@@ -18,7 +18,8 @@ from zerver.lib.sessions import (
     user_sessions,
 )
 from zerver.lib.test_classes import ZulipTestCase
-from zerver.models import Realm, UserProfile, get_realm
+from zerver.models import Realm, UserProfile
+from zerver.models.realms import get_realm
 
 
 class TestSessions(ZulipTestCase):
diff --git a/zerver/tests/test_signup.py b/zerver/tests/test_signup.py
index f41e1d7ab6..7210e55149 100644
--- a/zerver/tests/test_signup.py
+++ b/zerver/tests/test_signup.py
@@ -76,9 +76,9 @@ from zerver.models import (
     Subscription,
     UserMessage,
     UserProfile,
-    get_realm,
     get_stream,
 )
+from zerver.models.realms import get_realm
 from zerver.models.users import get_system_bot, get_user, get_user_by_delivery_email
 from zerver.views.auth import redirect_and_log_into_subdomain, start_two_factor_auth
 from zerver.views.development.registration import confirmation_key
diff --git a/zerver/tests/test_slack_importer.py b/zerver/tests/test_slack_importer.py
index b1c6d8473a..09d27bf805 100644
--- a/zerver/tests/test_slack_importer.py
+++ b/zerver/tests/test_slack_importer.py
@@ -48,7 +48,8 @@ from zerver.lib.import_realm import do_import_realm
 from zerver.lib.test_classes import ZulipTestCase
 from zerver.lib.test_helpers import read_test_image_file
 from zerver.lib.topic import EXPORT_TOPIC_NAME
-from zerver.models import Message, Realm, RealmAuditLog, Recipient, UserProfile, get_realm
+from zerver.models import Message, Realm, RealmAuditLog, Recipient, UserProfile
+from zerver.models.realms import get_realm
 
 
 def remove_folder(path: str) -> None:
diff --git a/zerver/tests/test_soft_deactivation.py b/zerver/tests/test_soft_deactivation.py
index 71f484f7e8..d6c9309235 100644
--- a/zerver/tests/test_soft_deactivation.py
+++ b/zerver/tests/test_soft_deactivation.py
@@ -27,9 +27,9 @@ from zerver.models import (
     UserActivity,
     UserMessage,
     UserProfile,
-    get_realm,
     get_stream,
 )
+from zerver.models.realms import get_realm
 
 logger_string = "zulip.soft_deactivation"
 
diff --git a/zerver/tests/test_subs.py b/zerver/tests/test_subs.py
index 23bb63cedb..a9a232cffe 100644
--- a/zerver/tests/test_subs.py
+++ b/zerver/tests/test_subs.py
@@ -105,11 +105,11 @@ from zerver.models import (
     UserMessage,
     UserProfile,
     get_default_stream_groups,
-    get_realm,
     get_stream,
     validate_attachment_request,
     validate_attachment_request_for_spectator_access,
 )
+from zerver.models.realms import get_realm
 from zerver.models.users import active_non_guest_user_ids, get_user, get_user_profile_by_id_in_realm
 from zerver.views.streams import compose_views
 
diff --git a/zerver/tests/test_upload.py b/zerver/tests/test_upload.py
index 115b81cd75..9efad08627 100644
--- a/zerver/tests/test_upload.py
+++ b/zerver/tests/test_upload.py
@@ -45,9 +45,9 @@ from zerver.models import (
     Realm,
     RealmDomain,
     UserProfile,
-    get_realm,
     validate_attachment_request,
 )
+from zerver.models.realms import get_realm
 from zerver.models.users import get_system_bot, get_user_by_delivery_email
 
 
diff --git a/zerver/tests/test_upload_local.py b/zerver/tests/test_upload_local.py
index 368436c7fe..850726a293 100644
--- a/zerver/tests/test_upload_local.py
+++ b/zerver/tests/test_upload_local.py
@@ -22,7 +22,8 @@ from zerver.lib.upload import (
 )
 from zerver.lib.upload.base import DEFAULT_EMOJI_SIZE, MEDIUM_AVATAR_SIZE, resize_avatar
 from zerver.lib.upload.local import write_local_file
-from zerver.models import Attachment, RealmEmoji, get_realm
+from zerver.models import Attachment, RealmEmoji
+from zerver.models.realms import get_realm
 from zerver.models.users import get_system_bot
 
 
diff --git a/zerver/tests/test_upload_s3.py b/zerver/tests/test_upload_s3.py
index 49716a0a6d..6e5c4c1993 100644
--- a/zerver/tests/test_upload_s3.py
+++ b/zerver/tests/test_upload_s3.py
@@ -36,7 +36,8 @@ from zerver.lib.upload.base import (
     resize_avatar,
 )
 from zerver.lib.upload.s3 import S3UploadBackend
-from zerver.models import Attachment, RealmEmoji, UserProfile, get_realm
+from zerver.models import Attachment, RealmEmoji, UserProfile
+from zerver.models.realms import get_realm
 from zerver.models.users import get_system_bot
 
 
diff --git a/zerver/tests/test_user_groups.py b/zerver/tests/test_user_groups.py
index dde4dced70..61b3a50770 100644
--- a/zerver/tests/test_user_groups.py
+++ b/zerver/tests/test_user_groups.py
@@ -32,15 +32,9 @@ from zerver.lib.user_groups import (
     is_user_in_group,
     user_groups_in_realm_serialized,
 )
-from zerver.models import (
-    GroupGroupMembership,
-    Realm,
-    UserGroup,
-    UserGroupMembership,
-    UserProfile,
-    get_realm,
-)
+from zerver.models import GroupGroupMembership, Realm, UserGroup, UserGroupMembership, UserProfile
 from zerver.models.groups import SystemGroups
+from zerver.models.realms import get_realm
 
 
 class UserGroupTestCase(ZulipTestCase):
diff --git a/zerver/tests/test_users.py b/zerver/tests/test_users.py
index 91ee3a0701..6a803ddb66 100644
--- a/zerver/tests/test_users.py
+++ b/zerver/tests/test_users.py
@@ -59,7 +59,6 @@ from zerver.lib.users import (
 from zerver.lib.utils import assert_is_not_none
 from zerver.models import (
     CustomProfileField,
-    InvalidFakeEmailDomainError,
     Message,
     OnboardingStep,
     PreregistrationUser,
@@ -76,11 +75,10 @@ from zerver.models import (
     check_valid_user_ids,
     filter_to_valid_prereg_users,
     get_client,
-    get_fake_email_domain,
-    get_realm,
     get_stream,
 )
 from zerver.models.groups import SystemGroups
+from zerver.models.realms import InvalidFakeEmailDomainError, get_fake_email_domain, get_realm
 from zerver.models.users import (
     get_source_profile,
     get_system_bot,
diff --git a/zerver/tests/test_webhooks_common.py b/zerver/tests/test_webhooks_common.py
index 444bd0d0e4..f4d55e2a33 100644
--- a/zerver/tests/test_webhooks_common.py
+++ b/zerver/tests/test_webhooks_common.py
@@ -21,7 +21,8 @@ from zerver.lib.webhooks.common import (
     standardize_headers,
     validate_extract_webhook_http_header,
 )
-from zerver.models import UserProfile, get_realm
+from zerver.models import UserProfile
+from zerver.models.realms import get_realm
 from zerver.models.users import get_user
 
 
diff --git a/zerver/tests/test_zephyr.py b/zerver/tests/test_zephyr.py
index 0721ce61ad..1ac021ce07 100644
--- a/zerver/tests/test_zephyr.py
+++ b/zerver/tests/test_zephyr.py
@@ -6,7 +6,7 @@ import orjson
 
 from zerver.lib.test_classes import ZulipTestCase
 from zerver.lib.users import get_api_key
-from zerver.models import get_realm
+from zerver.models.realms import get_realm
 from zerver.models.users import get_user
 
 if TYPE_CHECKING:
diff --git a/zerver/transaction_tests/test_user_groups.py b/zerver/transaction_tests/test_user_groups.py
index 42d407e3ba..0a5b639e38 100644
--- a/zerver/transaction_tests/test_user_groups.py
+++ b/zerver/transaction_tests/test_user_groups.py
@@ -12,7 +12,8 @@ from zerver.lib.exceptions import JsonableError
 from zerver.lib.test_classes import ZulipTransactionTestCase
 from zerver.lib.test_helpers import HostRequestMock
 from zerver.lib.user_groups import access_user_group_by_id
-from zerver.models import Realm, UserGroup, UserProfile, get_realm
+from zerver.models import Realm, UserGroup, UserProfile
+from zerver.models.realms import get_realm
 from zerver.views.user_groups import update_subgroups_of_user_group
 
 BARRIER: Optional[threading.Barrier] = None
diff --git a/zerver/views/auth.py b/zerver/views/auth.py
index 6f57ba1ed5..f434371c82 100644
--- a/zerver/views/auth.py
+++ b/zerver/views/auth.py
@@ -75,8 +75,8 @@ from zerver.models import (
     Realm,
     UserProfile,
     filter_to_valid_prereg_users,
-    get_realm,
 )
+from zerver.models.realms import get_realm
 from zerver.models.users import remote_user_to_email
 from zerver.signals import email_on_new_login
 from zerver.views.errors import config_error
diff --git a/zerver/views/development/dev_login.py b/zerver/views/development/dev_login.py
index be06d18c0e..f26296c47c 100644
--- a/zerver/views/development/dev_login.py
+++ b/zerver/views/development/dev_login.py
@@ -20,7 +20,8 @@ from zerver.lib.response import json_success
 from zerver.lib.subdomains import get_subdomain
 from zerver.lib.users import get_api_key
 from zerver.lib.validator import validate_login_email
-from zerver.models import Realm, UserProfile, get_realm
+from zerver.models import Realm, UserProfile
+from zerver.models.realms import get_realm
 from zerver.views.auth import get_safe_redirect_to
 from zerver.views.errors import config_error
 from zproject.backends import dev_auth_enabled
diff --git a/zerver/views/development/email_log.py b/zerver/views/development/email_log.py
index e359cecee2..1081634321 100644
--- a/zerver/views/development/email_log.py
+++ b/zerver/views/development/email_log.py
@@ -16,7 +16,8 @@ from zerver.actions.users import change_user_is_active
 from zerver.lib.email_notifications import enqueue_welcome_emails, send_account_registered_email
 from zerver.lib.request import REQ, has_request_variables
 from zerver.lib.response import json_success
-from zerver.models import Realm, get_realm, get_realm_stream
+from zerver.models import Realm, get_realm_stream
+from zerver.models.realms import get_realm
 from zerver.models.users import get_user_by_delivery_email
 from zerver.views.invite import INVITATION_LINK_VALIDITY_MINUTES
 from zproject.email_backends import get_forward_address, set_forward_address
diff --git a/zerver/views/development/integrations.py b/zerver/views/development/integrations.py
index 6ba0f006bd..0edab9d494 100644
--- a/zerver/views/development/integrations.py
+++ b/zerver/views/development/integrations.py
@@ -14,7 +14,8 @@ from zerver.lib.request import REQ, has_request_variables
 from zerver.lib.response import json_success
 from zerver.lib.validator import check_bool
 from zerver.lib.webhooks.common import get_fixture_http_headers, standardize_headers
-from zerver.models import UserProfile, get_realm
+from zerver.models import UserProfile
+from zerver.models.realms import get_realm
 
 if TYPE_CHECKING:
     from django.test.client import _MonkeyPatchedWSGIResponse as TestHttpResponse
diff --git a/zerver/views/realm_domains.py b/zerver/views/realm_domains.py
index c27de2cdbc..65ac5a0fe8 100644
--- a/zerver/views/realm_domains.py
+++ b/zerver/views/realm_domains.py
@@ -13,7 +13,8 @@ from zerver.lib.exceptions import JsonableError
 from zerver.lib.request import REQ, has_request_variables
 from zerver.lib.response import json_success
 from zerver.lib.validator import check_bool
-from zerver.models import RealmDomain, UserProfile, get_realm_domains
+from zerver.models import RealmDomain, UserProfile
+from zerver.models.realms import get_realm_domains
 
 
 def list_realm_domains(request: HttpRequest, user_profile: UserProfile) -> HttpResponse:
diff --git a/zerver/views/registration.py b/zerver/views/registration.py
index 6f25640037..6c4d3884d4 100644
--- a/zerver/views/registration.py
+++ b/zerver/views/registration.py
@@ -73,9 +73,6 @@ from zerver.lib.validator import (
 )
 from zerver.lib.zephyr import compute_mit_user_fullname
 from zerver.models import (
-    DisposableEmailError,
-    DomainNotAllowedForRealmError,
-    EmailContainsPlusError,
     MultiuseInvite,
     PreregistrationRealm,
     PreregistrationUser,
@@ -84,11 +81,16 @@ from zerver.models import (
     Stream,
     UserProfile,
     get_default_stream_groups,
+)
+from zerver.models.constants import MAX_LANGUAGE_ID_LENGTH
+from zerver.models.realms import (
+    DisposableEmailError,
+    DomainNotAllowedForRealmError,
+    EmailContainsPlusError,
     get_org_type_display_name,
     get_realm,
     name_changes_disabled,
 )
-from zerver.models.constants import MAX_LANGUAGE_ID_LENGTH
 from zerver.models.users import get_source_profile, get_user_by_delivery_email
 from zerver.views.auth import (
     create_preregistration_realm,
diff --git a/zerver/views/user_settings.py b/zerver/views/user_settings.py
index c073f35cbc..410e309e2e 100644
--- a/zerver/views/user_settings.py
+++ b/zerver/views/user_settings.py
@@ -52,12 +52,8 @@ from zerver.lib.validator import (
     check_string_in,
     check_timezone,
 )
-from zerver.models import (
-    EmailChangeStatus,
-    UserProfile,
-    avatar_changes_disabled,
-    name_changes_disabled,
-)
+from zerver.models import EmailChangeStatus, UserProfile
+from zerver.models.realms import avatar_changes_disabled, name_changes_disabled
 from zerver.views.auth import redirect_to_deactivation_notice
 from zproject.backends import check_password_strength, email_belongs_to_ldap
 
diff --git a/zerver/views/users.py b/zerver/views/users.py
index 5f9647b281..ca1317bde2 100644
--- a/zerver/views/users.py
+++ b/zerver/views/users.py
@@ -86,14 +86,12 @@ from zerver.lib.validator import (
     check_union,
     check_url,
 )
-from zerver.models import (
+from zerver.models import Service, Stream, UserProfile
+from zerver.models.realms import (
     DisposableEmailError,
     DomainNotAllowedForRealmError,
     EmailContainsPlusError,
     InvalidFakeEmailDomainError,
-    Service,
-    Stream,
-    UserProfile,
 )
 from zerver.models.users import (
     get_user_by_delivery_email,
diff --git a/zerver/views/video_calls.py b/zerver/views/video_calls.py
index 1c53c7f77e..09f2400379 100644
--- a/zerver/views/video_calls.py
+++ b/zerver/views/video_calls.py
@@ -32,7 +32,8 @@ from zerver.lib.response import json_success
 from zerver.lib.subdomains import get_subdomain
 from zerver.lib.url_encoding import append_url_query_string
 from zerver.lib.validator import check_bool, check_dict, check_string
-from zerver.models import UserProfile, get_realm
+from zerver.models import UserProfile
+from zerver.models.realms import get_realm
 
 
 class VideoCallSession(OutgoingSession):
diff --git a/zerver/webhooks/helloworld/tests.py b/zerver/webhooks/helloworld/tests.py
index 3ee3010f56..92cdee952e 100644
--- a/zerver/webhooks/helloworld/tests.py
+++ b/zerver/webhooks/helloworld/tests.py
@@ -1,7 +1,7 @@
 from django.conf import settings
 
 from zerver.lib.test_classes import WebhookTestCase
-from zerver.models import get_realm
+from zerver.models.realms import get_realm
 from zerver.models.users import get_system_bot
 
 
diff --git a/zerver/webhooks/teamcity/tests.py b/zerver/webhooks/teamcity/tests.py
index 50ac0d8bf7..39a11b4d80 100644
--- a/zerver/webhooks/teamcity/tests.py
+++ b/zerver/webhooks/teamcity/tests.py
@@ -2,7 +2,8 @@ import orjson
 
 from zerver.lib.send_email import FromAddress
 from zerver.lib.test_classes import WebhookTestCase
-from zerver.models import Recipient, get_realm
+from zerver.models import Recipient
+from zerver.models.realms import get_realm
 from zerver.models.users import get_user_by_delivery_email
 from zerver.webhooks.teamcity.view import MISCONFIGURED_PAYLOAD_TYPE_ERROR_MESSAGE
 
diff --git a/zilencer/management/commands/add_mock_conversation.py b/zilencer/management/commands/add_mock_conversation.py
index c4f50876cf..b424faaafb 100644
--- a/zilencer/management/commands/add_mock_conversation.py
+++ b/zilencer/management/commands/add_mock_conversation.py
@@ -11,7 +11,8 @@ from zerver.actions.user_settings import do_change_avatar_fields
 from zerver.lib.emoji import get_emoji_data
 from zerver.lib.streams import ensure_stream
 from zerver.lib.upload import upload_avatar_image
-from zerver.models import Message, UserProfile, get_realm
+from zerver.models import Message, UserProfile
+from zerver.models.realms import get_realm
 
 
 class Command(BaseCommand):
diff --git a/zilencer/management/commands/populate_billing_realms.py b/zilencer/management/commands/populate_billing_realms.py
index 752e826b75..941cd1682e 100644
--- a/zilencer/management/commands/populate_billing_realms.py
+++ b/zilencer/management/commands/populate_billing_realms.py
@@ -26,7 +26,8 @@ from zerver.actions.streams import bulk_add_subscriptions
 from zerver.apps import flush_cache
 from zerver.lib.remote_server import get_realms_info_for_push_bouncer
 from zerver.lib.streams import create_stream_if_needed
-from zerver.models import Realm, UserProfile, get_realm
+from zerver.models import Realm, UserProfile
+from zerver.models.realms import get_realm
 from zilencer.models import (
     RemoteRealm,
     RemoteRealmBillingUser,
diff --git a/zilencer/management/commands/populate_db.py b/zilencer/management/commands/populate_db.py
index eca2eefeb6..3cde92da31 100644
--- a/zilencer/management/commands/populate_db.py
+++ b/zilencer/management/commands/populate_db.py
@@ -67,9 +67,9 @@ from zerver.models import (
     flush_alert_word,
     get_client,
     get_or_create_huddle,
-    get_realm,
     get_stream,
 )
+from zerver.models.realms import get_realm
 from zerver.models.users import get_user, get_user_by_delivery_email, get_user_profile_by_id
 from zilencer.models import RemoteRealm, RemoteZulipServer
 from zilencer.views import update_remote_realm_data_for_server
diff --git a/zilencer/management/commands/sync_api_key.py b/zilencer/management/commands/sync_api_key.py
index 84458b2f47..dbd1a042a2 100644
--- a/zilencer/management/commands/sync_api_key.py
+++ b/zilencer/management/commands/sync_api_key.py
@@ -5,7 +5,8 @@ from typing import Any
 from django.core.management.base import BaseCommand
 from typing_extensions import override
 
-from zerver.models import UserProfile, get_realm
+from zerver.models import UserProfile
+from zerver.models.realms import get_realm
 from zerver.models.users import get_user_by_delivery_email
 
 
diff --git a/zproject/backends.py b/zproject/backends.py
index 3a2fdd2fb5..ecec01c762 100644
--- a/zproject/backends.py
+++ b/zproject/backends.py
@@ -103,9 +103,6 @@ from zerver.lib.url_encoding import append_url_query_string
 from zerver.lib.users import check_full_name, validate_user_custom_profile_field
 from zerver.models import (
     CustomProfileField,
-    DisposableEmailError,
-    DomainNotAllowedForRealmError,
-    EmailContainsPlusError,
     PreregistrationRealm,
     PreregistrationUser,
     Realm,
@@ -113,6 +110,11 @@ from zerver.models import (
     UserGroupMembership,
     UserProfile,
     custom_profile_fields_for_realm,
+)
+from zerver.models.realms import (
+    DisposableEmailError,
+    DomainNotAllowedForRealmError,
+    EmailContainsPlusError,
     get_realm,
     supported_auth_backends,
 )