diff --git a/corporate/lib/stripe.py b/corporate/lib/stripe.py
index 84addc5af5..af87512ca0 100644
--- a/corporate/lib/stripe.py
+++ b/corporate/lib/stripe.py
@@ -2240,7 +2240,7 @@ class BillingSession(ABC):
         # Should do this in JavaScript, using the user's time zone
         if plan.is_free_trial() or downgrade_at_end_of_free_trial:
             assert plan.next_invoice_date is not None
-            renewal_date = "{dt:%B} {dt.day}, {dt.year}".format(dt=plan.next_invoice_date)
+            renewal_date = f"{plan.next_invoice_date:%B} {plan.next_invoice_date.day}, {plan.next_invoice_date.year}"
         else:
             renewal_date = "{dt:%B} {dt.day}, {dt.year}".format(
                 dt=start_of_next_billing_cycle(plan, now)
diff --git a/scripts/lib/zulip_tools.py b/scripts/lib/zulip_tools.py
index 1287fa354b..fdfe5206ed 100755
--- a/scripts/lib/zulip_tools.py
+++ b/scripts/lib/zulip_tools.py
@@ -563,10 +563,10 @@ def assert_not_running_as_root() -> None:
     if is_root():
         pwent = get_zulip_pwent()
         msg = (
-            "{shortname} should not be run as root. Use `su {user}` to switch to the 'zulip'\n"
-            "user before rerunning this, or use \n  su {user} -c '{name} ...'\n"
+            f"{os.path.basename(script_name)} should not be run as root. Use `su {pwent.pw_name}` to switch to the 'zulip'\n"
+            f"user before rerunning this, or use \n  su {pwent.pw_name} -c '{script_name} ...'\n"
             "to switch users and run this as a single command."
-        ).format(name=script_name, shortname=os.path.basename(script_name), user=pwent.pw_name)
+        )
         print(msg)
         sys.exit(1)
 
diff --git a/tools/lib/provision.py b/tools/lib/provision.py
index 82d898164d..154958b97f 100755
--- a/tools/lib/provision.py
+++ b/tools/lib/provision.py
@@ -45,9 +45,7 @@ with open("/proc/meminfo") as meminfo:
 ram_gb = float(ram_size) / 1024.0 / 1024.0
 if ram_gb < 1.5:
     print(
-        "You have insufficient RAM ({} GB) to run the Zulip development environment.".format(
-            round(ram_gb, 2)
-        )
+        f"You have insufficient RAM ({round(ram_gb, 2)} GB) to run the Zulip development environment."
     )
     print("We recommend at least 2 GB of RAM, and require at least 1.5 GB.")
     sys.exit(1)
diff --git a/zerver/actions/create_realm.py b/zerver/actions/create_realm.py
index 8e264c157f..affb079190 100644
--- a/zerver/actions/create_realm.py
+++ b/zerver/actions/create_realm.py
@@ -325,13 +325,7 @@ def do_create_realm(
         support_url = get_realm_support_url(realm)
         organization_type = get_org_type_display_name(realm.org_type)
 
-        message = "[{name}]({support_link}) ([{subdomain}]({realm_link})). Organization type: {type}".format(
-            name=realm.name,
-            subdomain=realm.display_subdomain,
-            realm_link=realm.uri,
-            support_link=support_url,
-            type=organization_type,
-        )
+        message = f"[{realm.name}]({support_url}) ([{realm.display_subdomain}]({realm.uri})). Organization type: {organization_type}"
         topic_name = "new organizations"
 
         try:
diff --git a/zerver/lib/bot_storage.py b/zerver/lib/bot_storage.py
index 7b3a9163da..0dccb96a2b 100644
--- a/zerver/lib/bot_storage.py
+++ b/zerver/lib/bot_storage.py
@@ -45,9 +45,7 @@ def set_bot_storage(bot_profile: UserProfile, entries: List[Tuple[str, str]]) ->
     new_storage_size = get_bot_storage_size(bot_profile) + storage_size_difference
     if new_storage_size > storage_size_limit:
         raise StateError(
-            "Request exceeds storage limit by {} characters. The limit is {} characters.".format(
-                new_storage_size - storage_size_limit, storage_size_limit
-            )
+            f"Request exceeds storage limit by {new_storage_size - storage_size_limit} characters. The limit is {storage_size_limit} characters."
         )
     else:
         for key, value in entries:
diff --git a/zerver/lib/email_mirror.py b/zerver/lib/email_mirror.py
index d29a65943e..dd06f16330 100644
--- a/zerver/lib/email_mirror.py
+++ b/zerver/lib/email_mirror.py
@@ -205,9 +205,7 @@ def send_mm_reply_to_stream(
             message_content=body,
         )
     except JsonableError as error:
-        error_message = "Error sending message to stream {stream} via message notification email reply:\n{error}".format(
-            stream=stream.name, error=error.msg
-        )
+        error_message = f"Error sending message to stream {stream.name} via message notification email reply:\n{error.msg}"
         internal_send_private_message(
             get_system_bot(settings.NOTIFICATION_BOT, user_profile.realm_id),
             user_profile,
diff --git a/zerver/management/commands/deactivate_user.py b/zerver/management/commands/deactivate_user.py
index 6234daa54c..63f0f42ee8 100644
--- a/zerver/management/commands/deactivate_user.py
+++ b/zerver/management/commands/deactivate_user.py
@@ -37,10 +37,7 @@ class Command(ZulipBaseCommand):
             print(session.expire_date, session.get_decoded())
         print("")
         print(
-            "{} has {} active bots that will also be deactivated.".format(
-                user_profile.delivery_email,
-                get_active_bots_owned_by_user(user_profile).count(),
-            )
+            f"{user_profile.delivery_email} has {get_active_bots_owned_by_user(user_profile).count()} active bots that will also be deactivated."
         )
 
         if not options["for_real"]:
diff --git a/zerver/management/commands/delete_user.py b/zerver/management/commands/delete_user.py
index 9e32ed31df..dff58d3880 100644
--- a/zerver/management/commands/delete_user.py
+++ b/zerver/management/commands/delete_user.py
@@ -57,10 +57,7 @@ This will:
 
         for user_profile in user_profiles:
             print(
-                "{} has {} active bots that will be deactivated as a result of the user's deletion.".format(
-                    user_profile.delivery_email,
-                    get_active_bots_owned_by_user(user_profile).count(),
-                )
+                f"{user_profile.delivery_email} has {get_active_bots_owned_by_user(user_profile).count()} active bots that will be deactivated as a result of the user's deletion."
             )
 
         if not options["for_real"]:
diff --git a/zerver/tests/test_markdown.py b/zerver/tests/test_markdown.py
index 9610ee7788..b50a511f24 100644
--- a/zerver/tests/test_markdown.py
+++ b/zerver/tests/test_markdown.py
@@ -2875,9 +2875,7 @@ class MarkdownTest(ZulipTestCase):
         content = "#**Denmark**"
         self.assertEqual(
             render_message_markdown(msg, content).rendered_content,
-            '<p><a class="stream" data-stream-id="{d.id}" href="/#narrow/stream/{d.id}-Denmark">#{d.name}</a></p>'.format(
-                d=denmark,
-            ),
+            f'<p><a class="stream" data-stream-id="{denmark.id}" href="/#narrow/stream/{denmark.id}-Denmark">#{denmark.name}</a></p>',
         )
 
     def test_invalid_stream_followed_by_valid_mention(self) -> None:
@@ -2891,9 +2889,7 @@ class MarkdownTest(ZulipTestCase):
         content = "#**Invalid** and #**Denmark**"
         self.assertEqual(
             render_message_markdown(msg, content).rendered_content,
-            '<p>#<strong>Invalid</strong> and <a class="stream" data-stream-id="{d.id}" href="/#narrow/stream/{d.id}-Denmark">#{d.name}</a></p>'.format(
-                d=denmark,
-            ),
+            f'<p>#<strong>Invalid</strong> and <a class="stream" data-stream-id="{denmark.id}" href="/#narrow/stream/{denmark.id}-Denmark">#{denmark.name}</a></p>',
         )
 
     def test_stream_multiple(self) -> None:
@@ -2927,9 +2923,7 @@ class MarkdownTest(ZulipTestCase):
         content = "#**CaseSens**"
         self.assertEqual(
             render_message_markdown(msg, content).rendered_content,
-            '<p><a class="stream" data-stream-id="{s.id}" href="/#narrow/stream/{s.id}-{s.name}">#{s.name}</a></p>'.format(
-                s=case_sens,
-            ),
+            f'<p><a class="stream" data-stream-id="{case_sens.id}" href="/#narrow/stream/{case_sens.id}-{case_sens.name}">#{case_sens.name}</a></p>',
         )
 
     def test_stream_case_sensitivity_nonmatching(self) -> None:
@@ -2957,9 +2951,7 @@ class MarkdownTest(ZulipTestCase):
         content = "#**Denmark>some topic**"
         self.assertEqual(
             render_message_markdown(msg, content).rendered_content,
-            '<p><a class="stream-topic" data-stream-id="{d.id}" href="/#narrow/stream/{d.id}-Denmark/topic/some.20topic">#{d.name} &gt; some topic</a></p>'.format(
-                d=denmark,
-            ),
+            f'<p><a class="stream-topic" data-stream-id="{denmark.id}" href="/#narrow/stream/{denmark.id}-Denmark/topic/some.20topic">#{denmark.name} &gt; some topic</a></p>',
         )
 
     def test_topic_atomic_string(self) -> None:
@@ -2981,9 +2973,7 @@ class MarkdownTest(ZulipTestCase):
         content = "#**Denmark>#1234**"
         self.assertEqual(
             render_message_markdown(msg, content).rendered_content,
-            '<p><a class="stream-topic" data-stream-id="{d.id}" href="/#narrow/stream/{d.id}-Denmark/topic/.231234">#{d.name} &gt; #1234</a></p>'.format(
-                d=denmark,
-            ),
+            f'<p><a class="stream-topic" data-stream-id="{denmark.id}" href="/#narrow/stream/{denmark.id}-Denmark/topic/.231234">#{denmark.name} &gt; #1234</a></p>',
         )
 
     def test_topic_multiple(self) -> None:
@@ -3052,10 +3042,7 @@ class MarkdownTest(ZulipTestCase):
         href = f"/#narrow/stream/{stream.id}-Stream-.231234"
         self.assertEqual(
             render_message_markdown(msg, content).rendered_content,
-            '<p><a class="stream" data-stream-id="{s.id}" href="{href}">#{s.name}</a></p>'.format(
-                s=stream,
-                href=href,
-            ),
+            f'<p><a class="stream" data-stream-id="{stream.id}" href="{href}">#{stream.name}</a></p>',
         )
 
     def test_stream_invalid(self) -> None:
diff --git a/zerver/tests/test_retention.py b/zerver/tests/test_retention.py
index 86cc15f0c0..2cb90a95a3 100644
--- a/zerver/tests/test_retention.py
+++ b/zerver/tests/test_retention.py
@@ -194,10 +194,10 @@ class ArchiveMessagesTestingBase(RetentionTestingBase):
         self.subscribe(user_profile, "Denmark")
         body = (
             "Some files here ..."
-            " [zulip.txt](http://{host}/user_uploads/{id}/31/4CBjtTLYZhk66pZrF8hnYGwc/zulip.txt)"
-            " http://{host}/user_uploads/{id}/31/4CBjtTLYZhk66pZrF8hnYGwc/temp_file.py.... Some"
-            " more.... http://{host}/user_uploads/{id}/31/4CBjtTLYZhk66pZrF8hnYGwc/abc.py"
-        ).format(id=realm_id, host=host)
+            f" [zulip.txt](http://{host}/user_uploads/{realm_id}/31/4CBjtTLYZhk66pZrF8hnYGwc/zulip.txt)"
+            f" http://{host}/user_uploads/{realm_id}/31/4CBjtTLYZhk66pZrF8hnYGwc/temp_file.py.... Some"
+            f" more.... http://{host}/user_uploads/{realm_id}/31/4CBjtTLYZhk66pZrF8hnYGwc/abc.py"
+        )
 
         expired_message_id = self.send_stream_message(user_profile, "Denmark", body)
         actual_message_id = self.send_stream_message(user_profile, "Denmark", body)
@@ -754,13 +754,13 @@ class MoveMessageToArchiveGeneral(MoveMessageToArchiveBase):
         self._create_attachments()
         realm_id = get_realm("zulip").id
         host = get_realm("zulip").host
-        body = """Some files here ...[zulip.txt](
-            http://{host}/user_uploads/{id}/31/4CBjtTLYZhk66pZrF8hnYGwc/zulip.txt)
-            http://{host}/user_uploads/{id}/31/4CBjtTLYZhk66pZrF8hnYGwc/temp_file.py ....
-            Some more.... http://{host}/user_uploads/{id}/31/4CBjtTLYZhk66pZrF8hnYGwc/abc.py ...
-            http://{host}/user_uploads/{id}/31/4CBjtTLYZhk66pZrF8hnYGwc/new.py ....
-            http://{host}/user_uploads/{id}/31/4CBjtTLYZhk66pZrF8hnYGwc/hello.txt ....
-        """.format(id=realm_id, host=host)
+        body = f"""Some files here ...[zulip.txt](
+            http://{host}/user_uploads/{realm_id}/31/4CBjtTLYZhk66pZrF8hnYGwc/zulip.txt)
+            http://{host}/user_uploads/{realm_id}/31/4CBjtTLYZhk66pZrF8hnYGwc/temp_file.py ....
+            Some more.... http://{host}/user_uploads/{realm_id}/31/4CBjtTLYZhk66pZrF8hnYGwc/abc.py ...
+            http://{host}/user_uploads/{realm_id}/31/4CBjtTLYZhk66pZrF8hnYGwc/new.py ....
+            http://{host}/user_uploads/{realm_id}/31/4CBjtTLYZhk66pZrF8hnYGwc/hello.txt ....
+        """
 
         msg_id = self.send_personal_message(self.sender, self.recipient, body)
         # Simulate a reply with the same contents.
@@ -813,13 +813,13 @@ class MoveMessageToArchiveGeneral(MoveMessageToArchiveBase):
         self._create_attachments()
         realm_id = get_realm("zulip").id
         host = get_realm("zulip").host
-        body = """Some files here ...[zulip.txt](
-            http://{host}/user_uploads/{id}/31/4CBjtTLYZhk66pZrF8hnYGwc/zulip.txt)
-            http://{host}/user_uploads/{id}/31/4CBjtTLYZhk66pZrF8hnYGwc/temp_file.py ....
-            Some more.... http://{host}/user_uploads/{id}/31/4CBjtTLYZhk66pZrF8hnYGwc/abc.py ...
-            http://{host}/user_uploads/{id}/31/4CBjtTLYZhk66pZrF8hnYGwc/new.py ....
-            http://{host}/user_uploads/{id}/31/4CBjtTLYZhk66pZrF8hnYGwc/hello.txt ....
-        """.format(id=realm_id, host=host)
+        body = f"""Some files here ...[zulip.txt](
+            http://{host}/user_uploads/{realm_id}/31/4CBjtTLYZhk66pZrF8hnYGwc/zulip.txt)
+            http://{host}/user_uploads/{realm_id}/31/4CBjtTLYZhk66pZrF8hnYGwc/temp_file.py ....
+            Some more.... http://{host}/user_uploads/{realm_id}/31/4CBjtTLYZhk66pZrF8hnYGwc/abc.py ...
+            http://{host}/user_uploads/{realm_id}/31/4CBjtTLYZhk66pZrF8hnYGwc/new.py ....
+            http://{host}/user_uploads/{realm_id}/31/4CBjtTLYZhk66pZrF8hnYGwc/hello.txt ....
+        """
 
         msg_id = self.send_personal_message(self.sender, self.recipient, body)
 
diff --git a/zerver/tests/test_subs.py b/zerver/tests/test_subs.py
index 4457db2d1e..a57505cf06 100644
--- a/zerver/tests/test_subs.py
+++ b/zerver/tests/test_subs.py
@@ -3274,9 +3274,7 @@ class DefaultStreamGroupTest(ZulipTestCase):
         )
         self.assert_json_error(
             result,
-            "Default stream group name too long (limit: {} characters)".format(
-                DefaultStreamGroup.MAX_NAME_LENGTH
-            ),
+            f"Default stream group name too long (limit: {DefaultStreamGroup.MAX_NAME_LENGTH} characters)",
         )
 
         result = self.client_post(