diff --git a/analytics/views/stats.py b/analytics/views/stats.py
index cf05e23624..963358e262 100644
--- a/analytics/views/stats.py
+++ b/analytics/views/stats.py
@@ -315,7 +315,7 @@ def get_chart_data(
         labels_sort_function = None
         include_empty_subgroups = True
     else:
-        raise JsonableError(_("Unknown chart name: {}").format(chart_name))
+        raise JsonableError(_("Unknown chart name: {chart_name}").format(chart_name=chart_name))
 
     # Most likely someone using our API endpoint. The /stats page does not
     # pass a start or end in its requests.
diff --git a/corporate/lib/stripe.py b/corporate/lib/stripe.py
index c3112d54db..6f219e2140 100644
--- a/corporate/lib/stripe.py
+++ b/corporate/lib/stripe.py
@@ -109,14 +109,17 @@ def validate_licenses(
 
     if licenses is None or (not exempt_from_license_number_check and licenses < min_licenses):
         raise BillingError(
-            "not enough licenses", _("You must invoice for at least {} users.").format(min_licenses)
+            "not enough licenses",
+            _("You must invoice for at least {min_licenses} users.").format(
+                min_licenses=min_licenses
+            ),
         )
 
     if max_licenses is not None and licenses > max_licenses:
         message = _(
-            "Invoices with more than {} licenses can't be processed from this page. To complete "
-            "the upgrade, please contact {}."
-        ).format(max_licenses, settings.ZULIP_ADMINISTRATOR)
+            "Invoices with more than {max_licenses} licenses can't be processed from this page. To"
+            " complete the upgrade, please contact {email}."
+        ).format(max_licenses=max_licenses, email=settings.ZULIP_ADMINISTRATOR)
         raise BillingError("too many licenses", message)
 
 
diff --git a/tools/semgrep.yml b/tools/semgrep.yml
index 818805fc1b..8fee591531 100644
--- a/tools/semgrep.yml
+++ b/tools/semgrep.yml
@@ -76,6 +76,20 @@ rules:
     severity: ERROR
     message: "Immediately formatting a lazily translated string destroys its laziness"
 
+  - id: translated-positional-field
+    languages: [python]
+    patterns:
+      - pattern-either:
+          - pattern: django.utils.translation.gettext("$MESSAGE")
+          - pattern: django.utils.translation.pgettext($CONTEXT, "$MESSAGE")
+          - pattern: django.utils.translation.gettext_lazy("$MESSAGE")
+          - pattern: django.utils.translation.pgettext_lazy($CONTEXT, "$MESSAGE")
+      - metavariable-regex:
+          metavariable: $MESSAGE
+          regex: (^|.*[^{])(\{\{)*\{[:!}].*
+    severity: ERROR
+    message: "Prefer {named} fields over positional {} in translated strings"
+
   - id: mutable-default-type
     languages: [python]
     pattern-either:
@@ -99,7 +113,9 @@ rules:
     pattern-either:
       - pattern: '"..." % ...'
       - pattern: django.utils.translation.gettext(...) % ...
+      - pattern: django.utils.translation.pgettext(...) % ...
       - pattern: django.utils.translation.gettext_lazy(...) % ...
+      - pattern: django.utils.translation.pgettext_lazy(...) % ...
     severity: ERROR
     message: "Prefer f-strings or .format for string formatting"
 
diff --git a/zerver/actions/default_streams.py b/zerver/actions/default_streams.py
index 79518487a0..467d278648 100644
--- a/zerver/actions/default_streams.py
+++ b/zerver/actions/default_streams.py
@@ -21,18 +21,22 @@ from zerver.tornado.django_api import send_event_on_commit
 
 def check_default_stream_group_name(group_name: str) -> None:
     if group_name.strip() == "":
-        raise JsonableError(_("Invalid default stream group name '{}'").format(group_name))
+        raise JsonableError(
+            _("Invalid default stream group name '{group_name}'").format(group_name=group_name)
+        )
     if len(group_name) > DefaultStreamGroup.MAX_NAME_LENGTH:
         raise JsonableError(
-            _("Default stream group name too long (limit: {} characters)").format(
-                DefaultStreamGroup.MAX_NAME_LENGTH,
+            _("Default stream group name too long (limit: {max_length} characters)").format(
+                max_length=DefaultStreamGroup.MAX_NAME_LENGTH,
             )
         )
     for i in group_name:
         if ord(i) == 0:
             raise JsonableError(
-                _("Default stream group name '{}' contains NULL (0x00) characters.").format(
-                    group_name,
+                _(
+                    "Default stream group name '{group_name}' contains NULL (0x00) characters."
+                ).format(
+                    group_name=group_name,
                 )
             )
 
@@ -45,7 +49,9 @@ def lookup_default_stream_groups(
         try:
             default_stream_group = DefaultStreamGroup.objects.get(name=group_name, realm=realm)
         except DefaultStreamGroup.DoesNotExist:
-            raise JsonableError(_("Invalid default stream group {}").format(group_name))
+            raise JsonableError(
+                _("Invalid default stream group {group_name}").format(group_name=group_name)
+            )
         default_stream_groups.append(default_stream_group)
     return default_stream_groups
 
@@ -157,11 +163,17 @@ def do_change_default_stream_group_name(
 ) -> None:
     if group.name == new_group_name:
         raise JsonableError(
-            _("This default stream group is already named '{}'").format(new_group_name)
+            _("This default stream group is already named '{group_name}'").format(
+                group_name=new_group_name
+            )
         )
 
     if DefaultStreamGroup.objects.filter(name=new_group_name, realm=realm).exists():
-        raise JsonableError(_("Default stream group '{}' already exists").format(new_group_name))
+        raise JsonableError(
+            _("Default stream group '{group_name}' already exists").format(
+                group_name=new_group_name
+            )
+        )
 
     group.name = new_group_name
     group.save()
diff --git a/zerver/actions/message_flags.py b/zerver/actions/message_flags.py
index 4fb0be08b0..f10f86c1f6 100644
--- a/zerver/actions/message_flags.py
+++ b/zerver/actions/message_flags.py
@@ -254,11 +254,13 @@ def do_update_message_flags(
 ) -> int:
     valid_flags = [item for item in UserMessage.flags if item not in UserMessage.NON_API_FLAGS]
     if flag not in valid_flags:
-        raise JsonableError(_("Invalid flag: '{}'").format(flag))
+        raise JsonableError(_("Invalid flag: '{flag}'").format(flag=flag))
     if flag in UserMessage.NON_EDITABLE_FLAGS:
-        raise JsonableError(_("Flag not editable: '{}'").format(flag))
+        raise JsonableError(_("Flag not editable: '{flag}'").format(flag=flag))
     if operation not in ("add", "remove"):
-        raise JsonableError(_("Invalid message flag operation: '{}'").format(operation))
+        raise JsonableError(
+            _("Invalid message flag operation: '{operation}'").format(operation=operation)
+        )
     is_adding = operation == "add"
     flagattr = getattr(UserMessage.flags, flag)
     flag_target = flagattr if is_adding else 0
diff --git a/zerver/actions/typing.py b/zerver/actions/typing.py
index 0a103f9610..f18ddf020b 100644
--- a/zerver/actions/typing.py
+++ b/zerver/actions/typing.py
@@ -52,7 +52,7 @@ def check_send_typing_notification(sender: UserProfile, user_ids: List[int], ope
             # is relevant here.
             user_profile = get_user_by_id_in_realm_including_cross_realm(user_id, sender.realm)
         except UserProfile.DoesNotExist:
-            raise JsonableError(_("Invalid user ID {}").format(user_id))
+            raise JsonableError(_("Invalid user ID {user_id}").format(user_id=user_id))
         user_profiles.append(user_profile)
 
     do_send_typing_notification(
diff --git a/zerver/actions/user_groups.py b/zerver/actions/user_groups.py
index a42f92f8db..9ce26165d1 100644
--- a/zerver/actions/user_groups.py
+++ b/zerver/actions/user_groups.py
@@ -210,7 +210,7 @@ def check_add_user_group(
         do_send_create_user_group_event(user_group, initial_members)
         return user_group
     except django.db.utils.IntegrityError:
-        raise JsonableError(_("User group '{}' already exists.").format(name))
+        raise JsonableError(_("User group '{group_name}' already exists.").format(group_name=name))
 
 
 def do_send_user_group_update_event(
@@ -242,7 +242,7 @@ def do_update_user_group_name(
             ).decode(),
         )
     except django.db.utils.IntegrityError:
-        raise JsonableError(_("User group '{}' already exists.").format(name))
+        raise JsonableError(_("User group '{group_name}' already exists.").format(group_name=name))
     do_send_user_group_update_event(user_group, dict(name=name))
 
 
diff --git a/zerver/forms.py b/zerver/forms.py
index 16d90d0028..4c32272f4e 100644
--- a/zerver/forms.py
+++ b/zerver/forms.py
@@ -494,10 +494,10 @@ class OurAuthenticationForm(AuthenticationForm):
                 secs_to_freedom = int(e.secs_to_freedom)
                 error_message = _(
                     "You're making too many attempts to sign in."
-                    " Try again in {} seconds or contact your organization administrator"
+                    " Try again in {seconds} seconds or contact your organization administrator"
                     " for help."
                 )
-                raise ValidationError(error_message.format(secs_to_freedom))
+                raise ValidationError(error_message.format(seconds=secs_to_freedom))
 
             if return_data.get("inactive_realm"):
                 raise AssertionError("Programming error: inactive realm in authentication form")
diff --git a/zerver/lib/addressee.py b/zerver/lib/addressee.py
index 3fe8395516..567e021664 100644
--- a/zerver/lib/addressee.py
+++ b/zerver/lib/addressee.py
@@ -19,7 +19,7 @@ def get_user_profiles(emails: Iterable[str], realm: Realm) -> List[UserProfile]:
         try:
             user_profile = get_user_including_cross_realm(email, realm)
         except UserProfile.DoesNotExist:
-            raise JsonableError(_("Invalid email '{}'").format(email))
+            raise JsonableError(_("Invalid email '{email}'").format(email=email))
         user_profiles.append(user_profile)
     return user_profiles
 
@@ -30,7 +30,7 @@ def get_user_profiles_by_ids(user_ids: Iterable[int], realm: Realm) -> List[User
         try:
             user_profile = get_user_by_id_in_realm_including_cross_realm(user_id, realm)
         except UserProfile.DoesNotExist:
-            raise JsonableError(_("Invalid user ID {}").format(user_id))
+            raise JsonableError(_("Invalid user ID {user_id}").format(user_id=user_id))
         user_profiles.append(user_profile)
     return user_profiles
 
diff --git a/zerver/lib/emoji.py b/zerver/lib/emoji.py
index 43be22036c..818fd72e0c 100644
--- a/zerver/lib/emoji.py
+++ b/zerver/lib/emoji.py
@@ -85,7 +85,7 @@ def get_emoji_data(realm_id: int, emoji_name: str) -> EmojiData:
         emoji_code = name_to_codepoint[emoji_name]
         return EmojiData(emoji_code=emoji_code, reaction_type=Reaction.UNICODE_EMOJI)
 
-    raise JsonableError(_("Emoji '{}' does not exist").format(emoji_name))
+    raise JsonableError(_("Emoji '{emoji_name}' does not exist").format(emoji_name=emoji_name))
 
 
 def check_emoji_request(realm: Realm, emoji_name: str, emoji_code: str, emoji_type: str) -> None:
diff --git a/zerver/lib/narrow.py b/zerver/lib/narrow.py
index 5ff943dfbf..64acd4a2b7 100644
--- a/zerver/lib/narrow.py
+++ b/zerver/lib/narrow.py
@@ -105,7 +105,7 @@ def check_narrow_for_events(narrow: Collection[NarrowTerm]) -> None:
     for narrow_term in narrow:
         operator = narrow_term.operator
         if operator not in ["stream", "topic", "sender", "is"]:
-            raise JsonableError(_("Operator {} not supported.").format(operator))
+            raise JsonableError(_("Operator {operator} not supported.").format(operator=operator))
 
 
 def is_spectator_compatible(narrow: Iterable[Dict[str, Any]]) -> bool:
diff --git a/zerver/lib/push_notifications.py b/zerver/lib/push_notifications.py
index 46aeeee38b..604b3d3ed5 100644
--- a/zerver/lib/push_notifications.py
+++ b/zerver/lib/push_notifications.py
@@ -338,8 +338,8 @@ def parse_gcm_options(options: Dict[str, Any], data: Dict[str, Any]) -> str:
     if priority not in ("normal", "high"):
         raise JsonableError(
             _(
-                "Invalid GCM option to bouncer: priority {!r}",
-            ).format(priority)
+                "Invalid GCM option to bouncer: priority {priority!r}",
+            ).format(priority=priority)
         )
 
     if options:
@@ -348,8 +348,8 @@ def parse_gcm_options(options: Dict[str, Any], data: Dict[str, Any]) -> str:
         # one-way compatibility.
         raise JsonableError(
             _(
-                "Invalid GCM options to bouncer: {}",
-            ).format(orjson.dumps(options).decode())
+                "Invalid GCM options to bouncer: {options}",
+            ).format(options=orjson.dumps(options).decode())
         )
 
     return priority  # when this grows a second option, can make it a tuple
diff --git a/zerver/lib/remote_server.py b/zerver/lib/remote_server.py
index a12f1f79dd..61e20030c5 100644
--- a/zerver/lib/remote_server.py
+++ b/zerver/lib/remote_server.py
@@ -90,7 +90,7 @@ def send_to_push_bouncer(
         if "code" in result_dict and result_dict["code"] == "INVALID_ZULIP_SERVER":
             # Invalid Zulip server credentials should email this server's admins
             raise PushNotificationBouncerError(
-                _("Push notifications bouncer error: {}").format(msg)
+                _("Push notifications bouncer error: {error}").format(error=msg)
             )
         else:
             # But most other errors coming from the push bouncer
diff --git a/zerver/lib/request.py b/zerver/lib/request.py
index 3203b2da99..03b4732d64 100644
--- a/zerver/lib/request.py
+++ b/zerver/lib/request.py
@@ -439,7 +439,9 @@ def has_request_variables(
                 except orjson.JSONDecodeError:
                     if param.argument_type == "body":
                         raise InvalidJSONError(_("Malformed JSON"))
-                    raise JsonableError(_('Argument "{}" is not valid JSON.').format(post_var_name))
+                    raise JsonableError(
+                        _('Argument "{name}" is not valid JSON.').format(name=post_var_name)
+                    )
 
                 try:
                     val = param.json_validator(post_var_name, val)
diff --git a/zerver/lib/streams.py b/zerver/lib/streams.py
index 67a89bc246..522f4cffed 100644
--- a/zerver/lib/streams.py
+++ b/zerver/lib/streams.py
@@ -298,7 +298,9 @@ def access_stream_for_send_message(
         return
 
     # All other cases are an error.
-    raise JsonableError(_("Not authorized to send to stream '{}'").format(stream.name))
+    raise JsonableError(
+        _("Not authorized to send to stream '{stream_name}'").format(stream_name=stream.name)
+    )
 
 
 def check_for_exactly_one_stream_arg(stream_id: Optional[int], stream: Optional[str]) -> None:
@@ -456,7 +458,9 @@ def check_stream_name_available(realm: Realm, name: str) -> None:
     check_stream_name(name)
     try:
         get_stream(name, realm)
-        raise JsonableError(_("Stream name '{}' is already taken.").format(name))
+        raise JsonableError(
+            _("Stream name '{stream_name}' is already taken.").format(stream_name=name)
+        )
     except Stream.DoesNotExist:
         pass
 
@@ -464,7 +468,7 @@ def check_stream_name_available(realm: Realm, name: str) -> None:
 def access_stream_by_name(
     user_profile: UserProfile, stream_name: str, allow_realm_admin: bool = False
 ) -> Tuple[Stream, Optional[Subscription]]:
-    error = _("Invalid stream name '{}'").format(stream_name)
+    error = _("Invalid stream name '{stream_name}'").format(stream_name=stream_name)
     try:
         stream = get_realm_stream(stream_name, user_profile.realm_id)
     except Stream.DoesNotExist:
@@ -584,7 +588,7 @@ def can_access_stream_history(user_profile: UserProfile, stream: Stream) -> bool
 
     if stream.is_history_public_to_subscribers():
         # In this case, we check if the user is subscribed.
-        error = _("Invalid stream name '{}'").format(stream.name)
+        error = _("Invalid stream name '{stream_name}'").format(stream_name=stream.name)
         try:
             access_stream_common(user_profile, stream, error)
         except JsonableError:
@@ -728,8 +732,10 @@ def list_to_streams(
 
         if not autocreate:
             raise JsonableError(
-                _("Stream(s) ({}) do not exist").format(
-                    ", ".join(stream_dict["name"] for stream_dict in missing_stream_dicts),
+                _("Stream(s) ({stream_names}) do not exist").format(
+                    stream_names=", ".join(
+                        stream_dict["name"] for stream_dict in missing_stream_dicts
+                    ),
                 )
             )
 
@@ -764,7 +770,9 @@ def access_default_stream_group_by_id(realm: Realm, group_id: int) -> DefaultStr
     try:
         return DefaultStreamGroup.objects.get(realm=realm, id=group_id)
     except DefaultStreamGroup.DoesNotExist:
-        raise JsonableError(_("Default stream group with id '{}' does not exist.").format(group_id))
+        raise JsonableError(
+            _("Default stream group with id '{group_id}' does not exist.").format(group_id=group_id)
+        )
 
 
 def get_stream_by_narrow_operand_access_unchecked(operand: Union[str, int], realm: Realm) -> Stream:
diff --git a/zerver/lib/string_validation.py b/zerver/lib/string_validation.py
index 22420461cd..1536b0a80f 100644
--- a/zerver/lib/string_validation.py
+++ b/zerver/lib/string_validation.py
@@ -39,13 +39,17 @@ def check_stream_name(stream_name: str) -> None:
 
     if len(stream_name) > Stream.MAX_NAME_LENGTH:
         raise JsonableError(
-            _("Stream name too long (limit: {} characters).").format(Stream.MAX_NAME_LENGTH)
+            _("Stream name too long (limit: {max_length} characters).").format(
+                max_length=Stream.MAX_NAME_LENGTH
+            )
         )
 
     invalid_character_pos = check_string_is_printable(stream_name)
     if invalid_character_pos is not None:
         raise JsonableError(
-            _("Invalid character in stream name, at position {}!").format(invalid_character_pos)
+            _("Invalid character in stream name, at position {position}!").format(
+                position=invalid_character_pos
+            )
         )
 
 
@@ -56,5 +60,7 @@ def check_stream_topic(topic: str) -> None:
     invalid_character_pos = check_string_is_printable(topic)
     if invalid_character_pos is not None:
         raise JsonableError(
-            _("Invalid character in topic, at position {}!").format(invalid_character_pos)
+            _("Invalid character in topic, at position {position}!").format(
+                position=invalid_character_pos
+            )
         )
diff --git a/zerver/lib/user_groups.py b/zerver/lib/user_groups.py
index 99646e10a9..699cbefac2 100644
--- a/zerver/lib/user_groups.py
+++ b/zerver/lib/user_groups.py
@@ -63,7 +63,9 @@ def access_user_groups_as_potential_subgroups(
     valid_group_ids = [group.id for group in user_groups]
     invalid_group_ids = [group_id for group_id in user_group_ids if group_id not in valid_group_ids]
     if invalid_group_ids:
-        raise JsonableError(_("Invalid user group ID: {}").format(invalid_group_ids[0]))
+        raise JsonableError(
+            _("Invalid user group ID: {group_id}").format(group_id=invalid_group_ids[0])
+        )
 
     return list(user_groups)
 
@@ -81,21 +83,29 @@ def access_user_group_for_setting(
     user_group = access_user_group_by_id(user_group_id, user_profile, for_read=True)
 
     if require_system_group and not user_group.is_system_group:
-        raise JsonableError(_("'{}' must be a system user group.").format(setting_name))
+        raise JsonableError(
+            _("'{setting_name}' must be a system user group.").format(setting_name=setting_name)
+        )
 
     if not allow_internet_group and user_group.name == UserGroup.EVERYONE_ON_INTERNET_GROUP_NAME:
         raise JsonableError(
-            _("'{}' setting cannot be set to 'role:internet' group.").format(setting_name)
+            _("'{setting_name}' setting cannot be set to 'role:internet' group.").format(
+                setting_name=setting_name
+            )
         )
 
     if not allow_owners_group and user_group.name == UserGroup.OWNERS_GROUP_NAME:
         raise JsonableError(
-            _("'{}' setting cannot be set to 'role:owners' group.").format(setting_name)
+            _("'{setting_name}' setting cannot be set to 'role:owners' group.").format(
+                setting_name=setting_name
+            )
         )
 
     if not allow_nobody_group and user_group.name == UserGroup.NOBODY_GROUP_NAME:
         raise JsonableError(
-            _("'{}' setting cannot be set to 'role:nobody' group.").format(setting_name)
+            _("'{setting_name}' setting cannot be set to 'role:nobody' group.").format(
+                setting_name=setting_name
+            )
         )
 
     return user_group
@@ -104,12 +114,16 @@ def access_user_group_for_setting(
 def check_user_group_name(group_name: str) -> str:
     if len(group_name) > UserGroup.MAX_NAME_LENGTH:
         raise JsonableError(
-            _("User group name cannot exceed {} characters.").format(UserGroup.MAX_NAME_LENGTH)
+            _("User group name cannot exceed {max_length} characters.").format(
+                max_length=UserGroup.MAX_NAME_LENGTH
+            )
         )
 
     for invalid_prefix in UserGroup.INVALID_NAME_PREFIXES:
         if group_name.startswith(invalid_prefix):
-            raise JsonableError(_("User group name cannot start with '{}'.").format(invalid_prefix))
+            raise JsonableError(
+                _("User group name cannot start with '{prefix}'.").format(prefix=invalid_prefix)
+            )
 
     return group_name
 
diff --git a/zerver/lib/users.py b/zerver/lib/users.py
index ebcd8e15d8..6e57bd9bf1 100644
--- a/zerver/lib/users.py
+++ b/zerver/lib/users.py
@@ -92,13 +92,15 @@ def check_valid_bot_config(
                 config_options = {c[1]: c[2] for c in integration.config_options}
                 break
         if not config_options:
-            raise JsonableError(_("Invalid integration '{}'.").format(service_name))
+            raise JsonableError(
+                _("Invalid integration '{integration_name}'.").format(integration_name=service_name)
+            )
 
         missing_keys = set(config_options.keys()) - set(config_data.keys())
         if missing_keys:
             raise JsonableError(
-                _("Missing configuration parameters: {}").format(
-                    missing_keys,
+                _("Missing configuration parameters: {keys}").format(
+                    keys=missing_keys,
                 )
             )
 
@@ -106,7 +108,11 @@ def check_valid_bot_config(
             value = config_data[key]
             error = validator(key, value)
             if error is not None:
-                raise JsonableError(_("Invalid {} value {} ({})").format(key, value, error))
+                raise JsonableError(
+                    _("Invalid {key} value {value} ({error})").format(
+                        key=key, value=value, error=error
+                    )
+                )
 
     elif bot_type == UserProfile.EMBEDDED_BOT:
         try:
@@ -229,12 +235,12 @@ def user_ids_to_users(user_ids: Sequence[int], realm: Realm) -> List[UserProfile
     found_user_ids = user_profiles_by_id.keys()
     missed_user_ids = [user_id for user_id in user_ids if user_id not in found_user_ids]
     if missed_user_ids:
-        raise JsonableError(_("Invalid user ID: {}").format(missed_user_ids[0]))
+        raise JsonableError(_("Invalid user ID: {user_id}").format(user_id=missed_user_ids[0]))
 
     user_profiles = list(user_profiles_by_id.values())
     for user_profile in user_profiles:
         if user_profile.realm != realm:
-            raise JsonableError(_("Invalid user ID: {}").format(user_profile.id))
+            raise JsonableError(_("Invalid user ID: {user_id}").format(user_id=user_profile.id))
     return user_profiles
 
 
diff --git a/zerver/lib/validator.py b/zerver/lib/validator.py
index 977130f83b..08d4977815 100644
--- a/zerver/lib/validator.py
+++ b/zerver/lib/validator.py
@@ -314,7 +314,7 @@ def check_dict(
             delta_keys = set(val.keys()) - required_keys_set - optional_keys_set
             if len(delta_keys) != 0:
                 raise ValidationError(
-                    _("Unexpected arguments: {}").format(", ".join(list(delta_keys)))
+                    _("Unexpected arguments: {keys}").format(keys=", ".join(list(delta_keys)))
                 )
 
         return cast(Dict[str, ResultT], val)
diff --git a/zerver/lib/webhooks/common.py b/zerver/lib/webhooks/common.py
index 17e2b44095..3cc2851734 100644
--- a/zerver/lib/webhooks/common.py
+++ b/zerver/lib/webhooks/common.py
@@ -228,4 +228,6 @@ def unix_milliseconds_to_timestamp(milliseconds: Any, webhook: str) -> datetime:
         seconds = milliseconds / 1000
         return timestamp_to_datetime(seconds)
     except (ValueError, TypeError):
-        raise JsonableError(_("The {} webhook expects time in milliseconds.").format(webhook))
+        raise JsonableError(
+            _("The {webhook} webhook expects time in milliseconds.").format(webhook=webhook)
+        )
diff --git a/zerver/lib/zcommand.py b/zerver/lib/zcommand.py
index 8041f1e5da..e29335499b 100644
--- a/zerver/lib/zcommand.py
+++ b/zerver/lib/zcommand.py
@@ -76,4 +76,4 @@ def process_zcommands(content: str, user_profile: UserProfile) -> Dict[str, Any]
                 setting_value=False,
             )
         )
-    raise JsonableError(_("No such command: {}").format(command))
+    raise JsonableError(_("No such command: {command}").format(command=command))
diff --git a/zerver/models.py b/zerver/models.py
index edaad57610..45860f6562 100644
--- a/zerver/models.py
+++ b/zerver/models.py
@@ -1230,9 +1230,11 @@ def filter_pattern_validator(value: str) -> Pattern[str]:
     except re2.error as e:
         if len(e.args) >= 1:
             if isinstance(e.args[0], str):  # nocoverage
-                raise ValidationError(_("Bad regular expression: {}").format(e.args[0]))
+                raise ValidationError(_("Bad regular expression: {regex}").format(regex=e.args[0]))
             if isinstance(e.args[0], bytes):
-                raise ValidationError(_("Bad regular expression: {}").format(e.args[0].decode()))
+                raise ValidationError(
+                    _("Bad regular expression: {regex}").format(regex=e.args[0].decode())
+                )
         raise ValidationError(_("Unknown regular expression error"))  # nocoverage
 
     return regex
@@ -4697,13 +4699,15 @@ def check_valid_user_ids(realm_id: int, val: object, allow_deactivated: bool = F
         try:
             user_profile = get_user_profile_by_id_in_realm(user_id, realm)
         except UserProfile.DoesNotExist:
-            raise ValidationError(_("Invalid user ID: {}").format(user_id))
+            raise ValidationError(_("Invalid user ID: {user_id}").format(user_id=user_id))
 
         if not allow_deactivated and not user_profile.is_active:
-            raise ValidationError(_("User with ID {} is deactivated").format(user_id))
+            raise ValidationError(
+                _("User with ID {user_id} is deactivated").format(user_id=user_id)
+            )
 
         if user_profile.is_bot:
-            raise ValidationError(_("User with ID {} is a bot").format(user_id))
+            raise ValidationError(_("User with ID {user_id} is a bot").format(user_id=user_id))
 
     return user_ids
 
diff --git a/zerver/views/events_register.py b/zerver/views/events_register.py
index 5800fe5f81..4f703bf4f3 100644
--- a/zerver/views/events_register.py
+++ b/zerver/views/events_register.py
@@ -105,11 +105,13 @@ def events_register_backend(
         # These parameters must be false for anonymous requests.
         if client_gravatar:
             raise JsonableError(
-                _("Invalid '{}' parameter for anonymous request").format("client_gravatar")
+                _("Invalid '{key}' parameter for anonymous request").format(key="client_gravatar")
             )
         if include_subscribers:
             raise JsonableError(
-                _("Invalid '{}' parameter for anonymous request").format("include_subscribers")
+                _("Invalid '{key}' parameter for anonymous request").format(
+                    key="include_subscribers"
+                )
             )
 
         # Language set by spectator to be passed down to clients as user_settings.
diff --git a/zerver/views/hotspots.py b/zerver/views/hotspots.py
index bb00daccc3..11c24a5bd3 100644
--- a/zerver/views/hotspots.py
+++ b/zerver/views/hotspots.py
@@ -16,6 +16,6 @@ def mark_hotspot_as_read(
     request: HttpRequest, user: UserProfile, hotspot: str = REQ()
 ) -> HttpResponse:
     if hotspot not in ALL_HOTSPOTS:
-        raise JsonableError(_("Unknown hotspot: {}").format(hotspot))
+        raise JsonableError(_("Unknown hotspot: {hotspot}").format(hotspot=hotspot))
     do_mark_hotspot_as_read(user, hotspot)
     return json_success(request)
diff --git a/zerver/views/invite.py b/zerver/views/invite.py
index e7088e862d..88c69be101 100644
--- a/zerver/views/invite.py
+++ b/zerver/views/invite.py
@@ -79,7 +79,9 @@ def invite_users_backend(
             (stream, sub) = access_stream_by_id(user_profile, stream_id)
         except JsonableError:
             raise JsonableError(
-                _("Stream does not exist with id: {}. No invites were sent.").format(stream_id)
+                _("Stream does not exist with id: {stream_id}. No invites were sent.").format(
+                    stream_id=stream_id
+                )
             )
         streams.append(stream)
 
@@ -204,7 +206,11 @@ def generate_multiuse_invite_backend(
         try:
             (stream, sub) = access_stream_by_id(user_profile, stream_id)
         except JsonableError:
-            raise JsonableError(_("Invalid stream ID {}. No invites were sent.").format(stream_id))
+            raise JsonableError(
+                _("Invalid stream ID {stream_id}. No invites were sent.").format(
+                    stream_id=stream_id
+                )
+            )
         streams.append(stream)
 
     invite_link = do_create_multiuse_invite_link(
diff --git a/zerver/views/message_fetch.py b/zerver/views/message_fetch.py
index 0a5b6a0812..0752feb82a 100644
--- a/zerver/views/message_fetch.py
+++ b/zerver/views/message_fetch.py
@@ -96,8 +96,8 @@ def get_messages_backend(
     anchor = parse_anchor_value(anchor_val, use_first_unread_anchor_val)
     if num_before + num_after > MAX_MESSAGES_PER_FETCH:
         raise JsonableError(
-            _("Too many messages requested (maximum {}).").format(
-                MAX_MESSAGES_PER_FETCH,
+            _("Too many messages requested (maximum {max_messages}).").format(
+                max_messages=MAX_MESSAGES_PER_FETCH,
             )
         )
     if num_before > 0 and num_after > 0 and not include_anchor:
diff --git a/zerver/views/message_flags.py b/zerver/views/message_flags.py
index 29f6ec1f5d..d366fa899d 100644
--- a/zerver/views/message_flags.py
+++ b/zerver/views/message_flags.py
@@ -166,7 +166,7 @@ def mark_topic_as_read(
         )
 
         if not topic_exists:
-            raise JsonableError(_("No such topic '{}'").format(topic_name))
+            raise JsonableError(_("No such topic '{topic}'").format(topic=topic_name))
 
     count = do_mark_stream_messages_as_read(user_profile, stream.recipient_id, topic_name)
 
diff --git a/zerver/views/presence.py b/zerver/views/presence.py
index 0773ba0c8b..468f509717 100644
--- a/zerver/views/presence.py
+++ b/zerver/views/presence.py
@@ -143,7 +143,7 @@ def update_active_status_backend(
 ) -> HttpResponse:
     status_val = UserPresence.status_from_string(status)
     if status_val is None:
-        raise JsonableError(_("Invalid status: {}").format(status))
+        raise JsonableError(_("Invalid status: {status}").format(status=status))
     elif user_profile.presence_enabled:
         client = RequestNotes.get_notes(request).client
         assert client is not None
diff --git a/zerver/views/realm.py b/zerver/views/realm.py
index 066cf21491..77619cfea1 100644
--- a/zerver/views/realm.py
+++ b/zerver/views/realm.py
@@ -157,7 +157,7 @@ def update_realm(
     # Additional validation/error checking beyond types go here, so
     # the entire request can succeed or fail atomically.
     if default_language is not None and default_language not in get_available_language_codes():
-        raise JsonableError(_("Invalid language '{}'").format(default_language))
+        raise JsonableError(_("Invalid language '{language}'").format(language=default_language))
     if authentication_methods is not None:
         if not user_profile.is_realm_owner:
             raise OrganizationOwnerRequiredError
@@ -166,11 +166,17 @@ def update_realm(
     if video_chat_provider is not None and video_chat_provider not in {
         p["id"] for p in Realm.VIDEO_CHAT_PROVIDERS.values()
     }:
-        raise JsonableError(_("Invalid video_chat_provider {}").format(video_chat_provider))
+        raise JsonableError(
+            _("Invalid video_chat_provider {video_chat_provider}").format(
+                video_chat_provider=video_chat_provider
+            )
+        )
     if giphy_rating is not None and giphy_rating not in {
         p["id"] for p in Realm.GIPHY_RATING_OPTIONS.values()
     }:
-        raise JsonableError(_("Invalid giphy_rating {}").format(giphy_rating))
+        raise JsonableError(
+            _("Invalid giphy_rating {giphy_rating}").format(giphy_rating=giphy_rating)
+        )
 
     message_retention_days: Optional[int] = None
     if message_retention_days_raw is not None:
diff --git a/zerver/views/realm_domains.py b/zerver/views/realm_domains.py
index b4bef5bac1..c27de2cdbc 100644
--- a/zerver/views/realm_domains.py
+++ b/zerver/views/realm_domains.py
@@ -33,7 +33,7 @@ def create_realm_domain(
     try:
         validate_domain(domain)
     except ValidationError as e:
-        raise JsonableError(_("Invalid domain: {}").format(e.messages[0]))
+        raise JsonableError(_("Invalid domain: {error}").format(error=e.messages[0]))
     if RealmDomain.objects.filter(realm=user_profile.realm, domain=domain).exists():
         raise JsonableError(
             _("The domain {domain} is already a part of your organization.").format(domain=domain)
diff --git a/zerver/views/realm_emoji.py b/zerver/views/realm_emoji.py
index e7389a0a2f..c0bc66b0a7 100644
--- a/zerver/views/realm_emoji.py
+++ b/zerver/views/realm_emoji.py
@@ -45,8 +45,8 @@ def upload_emoji(
     assert emoji_file.size is not None
     if (settings.MAX_EMOJI_FILE_SIZE_MIB * 1024 * 1024) < emoji_file.size:
         raise JsonableError(
-            _("Uploaded file is larger than the allowed limit of {} MiB").format(
-                settings.MAX_EMOJI_FILE_SIZE_MIB,
+            _("Uploaded file is larger than the allowed limit of {max_size} MiB").format(
+                max_size=settings.MAX_EMOJI_FILE_SIZE_MIB,
             )
         )
 
@@ -58,7 +58,9 @@ def delete_emoji(request: HttpRequest, user_profile: UserProfile, emoji_name: st
     if not RealmEmoji.objects.filter(
         realm=user_profile.realm, name=emoji_name, deactivated=False
     ).exists():
-        raise ResourceNotFoundError(_("Emoji '{}' does not exist").format(emoji_name))
+        raise ResourceNotFoundError(
+            _("Emoji '{emoji_name}' does not exist").format(emoji_name=emoji_name)
+        )
     check_remove_custom_emoji(user_profile, emoji_name)
     do_remove_realm_emoji(user_profile.realm, emoji_name, acting_user=user_profile)
     return json_success(request)
diff --git a/zerver/views/realm_icon.py b/zerver/views/realm_icon.py
index ed86606f09..683dde730c 100644
--- a/zerver/views/realm_icon.py
+++ b/zerver/views/realm_icon.py
@@ -24,8 +24,8 @@ def upload_icon(request: HttpRequest, user_profile: UserProfile) -> HttpResponse
     assert icon_file.size is not None
     if (settings.MAX_ICON_FILE_SIZE_MIB * 1024 * 1024) < icon_file.size:
         raise JsonableError(
-            _("Uploaded file is larger than the allowed limit of {} MiB").format(
-                settings.MAX_ICON_FILE_SIZE_MIB,
+            _("Uploaded file is larger than the allowed limit of {max_size} MiB").format(
+                max_size=settings.MAX_ICON_FILE_SIZE_MIB,
             )
         )
     upload_icon_image(icon_file, user_profile)
diff --git a/zerver/views/realm_logo.py b/zerver/views/realm_logo.py
index 6339062024..0a712ab172 100644
--- a/zerver/views/realm_logo.py
+++ b/zerver/views/realm_logo.py
@@ -30,8 +30,8 @@ def upload_logo(
     assert logo_file.size is not None
     if (settings.MAX_LOGO_FILE_SIZE_MIB * 1024 * 1024) < logo_file.size:
         raise JsonableError(
-            _("Uploaded file is larger than the allowed limit of {} MiB").format(
-                settings.MAX_LOGO_FILE_SIZE_MIB,
+            _("Uploaded file is larger than the allowed limit of {max_size} MiB").format(
+                max_size=settings.MAX_LOGO_FILE_SIZE_MIB,
             )
         )
     upload_logo_image(logo_file, user_profile, night)
diff --git a/zerver/views/streams.py b/zerver/views/streams.py
index 5322acfb1b..534a70ed70 100644
--- a/zerver/views/streams.py
+++ b/zerver/views/streams.py
@@ -1052,11 +1052,15 @@ def update_subscription_properties_backend(
         value = change["value"]
 
         if property not in property_converters:
-            raise JsonableError(_("Unknown subscription property: {}").format(property))
+            raise JsonableError(
+                _("Unknown subscription property: {property}").format(property=property)
+            )
 
         (stream, sub) = access_stream_by_id(user_profile, stream_id)
         if sub is None:
-            raise JsonableError(_("Not subscribed to stream id {}").format(stream_id))
+            raise JsonableError(
+                _("Not subscribed to stream id {stream_id}").format(stream_id=stream_id)
+            )
 
         try:
             value = property_converters[property](property, value)
diff --git a/zerver/views/upload.py b/zerver/views/upload.py
index b39fec0d41..fbe5caaf25 100644
--- a/zerver/views/upload.py
+++ b/zerver/views/upload.py
@@ -275,8 +275,8 @@ def upload_file_backend(request: HttpRequest, user_profile: UserProfile) -> Http
     assert file_size is not None
     if settings.MAX_FILE_UPLOAD_SIZE * 1024 * 1024 < file_size:
         raise JsonableError(
-            _("Uploaded file is larger than the allowed limit of {} MiB").format(
-                settings.MAX_FILE_UPLOAD_SIZE,
+            _("Uploaded file is larger than the allowed limit of {max_size} MiB").format(
+                max_size=settings.MAX_FILE_UPLOAD_SIZE,
             )
         )
     check_upload_within_quota(user_profile.realm, file_size)
diff --git a/zerver/views/user_groups.py b/zerver/views/user_groups.py
index b37de2d481..0b1d103aad 100644
--- a/zerver/views/user_groups.py
+++ b/zerver/views/user_groups.py
@@ -265,7 +265,9 @@ def remove_members_from_group_backend(
     group_member_ids = get_user_group_direct_member_ids(user_group)
     for member in members:
         if member not in group_member_ids:
-            raise JsonableError(_("There is no member '{}' in this user group").format(member))
+            raise JsonableError(
+                _("There is no member '{user_id}' in this user group").format(user_id=member)
+            )
 
     user_profile_ids = [user.id for user in user_profiles]
     remove_members_from_user_group(user_group, user_profile_ids, acting_user=user_profile)
diff --git a/zerver/views/user_settings.py b/zerver/views/user_settings.py
index 7073a8151f..90bb7244c3 100644
--- a/zerver/views/user_settings.py
+++ b/zerver/views/user_settings.py
@@ -130,7 +130,11 @@ def check_settings_values(
         and notification_sound not in get_available_notification_sounds()
         and notification_sound != "none"
     ):
-        raise JsonableError(_("Invalid notification sound '{}'").format(notification_sound))
+        raise JsonableError(
+            _("Invalid notification sound '{notification_sound}'").format(
+                notification_sound=notification_sound
+            )
+        )
 
     if email_notifications_batching_period_seconds is not None and (
         email_notifications_batching_period_seconds <= 0
@@ -138,8 +142,8 @@ def check_settings_values(
     ):
         # We set a limit of one week for the batching period
         raise JsonableError(
-            _("Invalid email batching period: {} seconds").format(
-                email_notifications_batching_period_seconds
+            _("Invalid email batching period: {seconds} seconds").format(
+                seconds=email_notifications_batching_period_seconds
             )
         )
 
@@ -275,8 +279,8 @@ def json_change_settings(
             assert e.secs_to_freedom is not None
             secs_to_freedom = int(e.secs_to_freedom)
             raise JsonableError(
-                _("You're making too many attempts! Try again in {} seconds.").format(
-                    secs_to_freedom
+                _("You're making too many attempts! Try again in {seconds} seconds.").format(
+                    seconds=secs_to_freedom
                 ),
             )
 
@@ -364,8 +368,8 @@ def set_avatar_backend(request: HttpRequest, user_profile: UserProfile) -> HttpR
     assert user_file.size is not None
     if (settings.MAX_AVATAR_FILE_SIZE_MIB * 1024 * 1024) < user_file.size:
         raise JsonableError(
-            _("Uploaded file is larger than the allowed limit of {} MiB").format(
-                settings.MAX_AVATAR_FILE_SIZE_MIB,
+            _("Uploaded file is larger than the allowed limit of {max_size} MiB").format(
+                max_size=settings.MAX_AVATAR_FILE_SIZE_MIB,
             )
         )
     upload_avatar_image(user_file, user_profile, user_profile)
diff --git a/zerver/views/users.py b/zerver/views/users.py
index 8fd247fcb8..1bbc4893b5 100644
--- a/zerver/views/users.py
+++ b/zerver/views/users.py
@@ -709,7 +709,7 @@ def create_user_backend(
 
     try:
         get_user_by_delivery_email(email, user_profile.realm)
-        raise JsonableError(_("Email '{}' already in use").format(email))
+        raise JsonableError(_("Email '{email}' already in use").format(email=email))
     except UserProfile.DoesNotExist:
         pass
 
diff --git a/zerver/webhooks/wordpress/view.py b/zerver/webhooks/wordpress/view.py
index bdce82434d..799e331413 100644
--- a/zerver/webhooks/wordpress/view.py
+++ b/zerver/webhooks/wordpress/view.py
@@ -53,7 +53,7 @@ def api_wordpress_webhook(
         data = WP_LOGIN_TEMPLATE.format(name=user_login)
 
     else:
-        raise JsonableError(_("Unknown WordPress webhook action: {}").format(hook))
+        raise JsonableError(_("Unknown WordPress webhook action: {hook}").format(hook=hook))
 
     topic = "WordPress notification"
 
diff --git a/zilencer/views.py b/zilencer/views.py
index f4859f6a45..6174549ad3 100644
--- a/zilencer/views.py
+++ b/zilencer/views.py
@@ -106,7 +106,7 @@ def register_remote_server(
         url_validator = URLValidator()
         url_validator("http://" + hostname)
     except ValidationError:
-        raise JsonableError(_("{} is not a valid hostname").format(hostname))
+        raise JsonableError(_("{hostname} is not a valid hostname").format(hostname=hostname))
 
     try:
         validate_email(contact_email)
@@ -370,7 +370,7 @@ def validate_incoming_table_data(
     last_id = get_last_id_from_server(server, model)
     for row in rows:
         if is_count_stat and row["property"] not in COUNT_STATS:
-            raise JsonableError(_("Invalid property {}").format(row["property"]))
+            raise JsonableError(_("Invalid property {property}").format(property=row["property"]))
         if row["id"] <= last_id:
             raise JsonableError(_("Data is out of order."))
         last_id = row["id"]