diff --git a/changelog.d/14885.misc b/changelog.d/14885.misc
new file mode 100644
index 000000000..9f5384e60
--- /dev/null
+++ b/changelog.d/14885.misc
@@ -0,0 +1 @@
+Add missing type hints.
\ No newline at end of file
diff --git a/mypy.ini b/mypy.ini
index 468bfe588..3bbf62c95 100644
--- a/mypy.ini
+++ b/mypy.ini
@@ -33,7 +33,6 @@ exclude = (?x)
    |synapse/storage/schema/
 
    |tests/api/test_auth.py
-   |tests/api/test_ratelimiting.py
    |tests/app/test_openid_listener.py
    |tests/appservice/test_scheduler.py
    |tests/events/test_presence_router.py
diff --git a/tests/api/test_ratelimiting.py b/tests/api/test_ratelimiting.py
index c86f783c5..b5fd08d43 100644
--- a/tests/api/test_ratelimiting.py
+++ b/tests/api/test_ratelimiting.py
@@ -8,7 +8,10 @@ from tests import unittest
 class TestRatelimiter(unittest.HomeserverTestCase):
     def test_allowed_via_can_do_action(self):
         limiter = Ratelimiter(
-            store=self.hs.get_datastores().main, clock=None, rate_hz=0.1, burst_count=1
+            store=self.hs.get_datastores().main,
+            clock=self.clock,
+            rate_hz=0.1,
+            burst_count=1,
         )
         allowed, time_allowed = self.get_success_or_raise(
             limiter.can_do_action(None, key="test_id", _time_now_s=0)
@@ -30,7 +33,7 @@ class TestRatelimiter(unittest.HomeserverTestCase):
 
     def test_allowed_appservice_ratelimited_via_can_requester_do_action(self):
         appservice = ApplicationService(
-            None,
+            token="fake_token",
             id="foo",
             rate_limited=True,
             sender="@as:example.com",
@@ -38,7 +41,10 @@ class TestRatelimiter(unittest.HomeserverTestCase):
         as_requester = create_requester("@user:example.com", app_service=appservice)
 
         limiter = Ratelimiter(
-            store=self.hs.get_datastores().main, clock=None, rate_hz=0.1, burst_count=1
+            store=self.hs.get_datastores().main,
+            clock=self.clock,
+            rate_hz=0.1,
+            burst_count=1,
         )
         allowed, time_allowed = self.get_success_or_raise(
             limiter.can_do_action(as_requester, _time_now_s=0)
@@ -60,7 +66,7 @@ class TestRatelimiter(unittest.HomeserverTestCase):
 
     def test_allowed_appservice_via_can_requester_do_action(self):
         appservice = ApplicationService(
-            None,
+            token="fake_token",
             id="foo",
             rate_limited=False,
             sender="@as:example.com",
@@ -68,7 +74,10 @@ class TestRatelimiter(unittest.HomeserverTestCase):
         as_requester = create_requester("@user:example.com", app_service=appservice)
 
         limiter = Ratelimiter(
-            store=self.hs.get_datastores().main, clock=None, rate_hz=0.1, burst_count=1
+            store=self.hs.get_datastores().main,
+            clock=self.clock,
+            rate_hz=0.1,
+            burst_count=1,
         )
         allowed, time_allowed = self.get_success_or_raise(
             limiter.can_do_action(as_requester, _time_now_s=0)
@@ -90,7 +99,10 @@ class TestRatelimiter(unittest.HomeserverTestCase):
 
     def test_allowed_via_ratelimit(self):
         limiter = Ratelimiter(
-            store=self.hs.get_datastores().main, clock=None, rate_hz=0.1, burst_count=1
+            store=self.hs.get_datastores().main,
+            clock=self.clock,
+            rate_hz=0.1,
+            burst_count=1,
         )
 
         # Shouldn't raise
@@ -114,7 +126,10 @@ class TestRatelimiter(unittest.HomeserverTestCase):
         """
         # Create a Ratelimiter with a very low allowed rate_hz and burst_count
         limiter = Ratelimiter(
-            store=self.hs.get_datastores().main, clock=None, rate_hz=0.1, burst_count=1
+            store=self.hs.get_datastores().main,
+            clock=self.clock,
+            rate_hz=0.1,
+            burst_count=1,
         )
 
         # First attempt should be allowed
@@ -160,7 +175,10 @@ class TestRatelimiter(unittest.HomeserverTestCase):
         """
         # Create a Ratelimiter with a very low allowed rate_hz and burst_count
         limiter = Ratelimiter(
-            store=self.hs.get_datastores().main, clock=None, rate_hz=0.1, burst_count=1
+            store=self.hs.get_datastores().main,
+            clock=self.clock,
+            rate_hz=0.1,
+            burst_count=1,
         )
 
         # First attempt should be allowed
@@ -188,7 +206,10 @@ class TestRatelimiter(unittest.HomeserverTestCase):
 
     def test_pruning(self):
         limiter = Ratelimiter(
-            store=self.hs.get_datastores().main, clock=None, rate_hz=0.1, burst_count=1
+            store=self.hs.get_datastores().main,
+            clock=self.clock,
+            rate_hz=0.1,
+            burst_count=1,
         )
         self.get_success_or_raise(
             limiter.can_do_action(None, key="test_id_1", _time_now_s=0)
@@ -223,7 +244,7 @@ class TestRatelimiter(unittest.HomeserverTestCase):
             )
         )
 
-        limiter = Ratelimiter(store=store, clock=None, rate_hz=0.1, burst_count=1)
+        limiter = Ratelimiter(store=store, clock=self.clock, rate_hz=0.1, burst_count=1)
 
         # Shouldn't raise
         for _ in range(20):
@@ -231,7 +252,10 @@ class TestRatelimiter(unittest.HomeserverTestCase):
 
     def test_multiple_actions(self):
         limiter = Ratelimiter(
-            store=self.hs.get_datastores().main, clock=None, rate_hz=0.1, burst_count=3
+            store=self.hs.get_datastores().main,
+            clock=self.clock,
+            rate_hz=0.1,
+            burst_count=3,
         )
         # Test that 4 actions aren't allowed with a maximum burst of 3.
         allowed, time_allowed = self.get_success_or_raise(
@@ -295,7 +319,10 @@ class TestRatelimiter(unittest.HomeserverTestCase):
         extra tokens by timing requests.
         """
         limiter = Ratelimiter(
-            store=self.hs.get_datastores().main, clock=None, rate_hz=0.1, burst_count=3
+            store=self.hs.get_datastores().main,
+            clock=self.clock,
+            rate_hz=0.1,
+            burst_count=3,
         )
 
         def consume_at(time: float) -> bool:
@@ -317,7 +344,10 @@ class TestRatelimiter(unittest.HomeserverTestCase):
 
     def test_record_action_which_doesnt_fill_bucket(self) -> None:
         limiter = Ratelimiter(
-            store=self.hs.get_datastores().main, clock=None, rate_hz=0.1, burst_count=3
+            store=self.hs.get_datastores().main,
+            clock=self.clock,
+            rate_hz=0.1,
+            burst_count=3,
         )
 
         # Observe two actions, leaving room in the bucket for one more.
@@ -337,7 +367,10 @@ class TestRatelimiter(unittest.HomeserverTestCase):
 
     def test_record_action_which_fills_bucket(self) -> None:
         limiter = Ratelimiter(
-            store=self.hs.get_datastores().main, clock=None, rate_hz=0.1, burst_count=3
+            store=self.hs.get_datastores().main,
+            clock=self.clock,
+            rate_hz=0.1,
+            burst_count=3,
         )
 
         # Observe three actions, filling up the bucket.
@@ -363,7 +396,10 @@ class TestRatelimiter(unittest.HomeserverTestCase):
 
     def test_record_action_which_overfills_bucket(self) -> None:
         limiter = Ratelimiter(
-            store=self.hs.get_datastores().main, clock=None, rate_hz=0.1, burst_count=3
+            store=self.hs.get_datastores().main,
+            clock=self.clock,
+            rate_hz=0.1,
+            burst_count=3,
         )
 
         # Observe four actions, exceeding the bucket.