diff --git a/trafficlight/internals/client.py b/trafficlight/internals/client.py
index 8b7f342..5d19e8d 100644
--- a/trafficlight/internals/client.py
+++ b/trafficlight/internals/client.py
@@ -1,6 +1,6 @@
 import asyncio
 import logging
-from typing import Any, Dict, Optional, Union
+from typing import Any, Dict, Optional, Union, cast
 
 from trafficlight.homerunner import HomeServer
 
@@ -174,10 +174,11 @@ async def accept_crosssign(self) -> None:
     async def verify_crosssign(self) -> None:
         await self._perform_action({"action": "verify_crosssign_emoji", "data": {}})
 
-    async def create_room(self, room_name: str) -> None:
-        await self._perform_action(
+    async def create_room(self, room_name: str) -> str:
+        response = await self._perform_action(
             {"action": "create_room", "data": {"name": room_name}}
         )
+        return cast(str, response["roomId"])
 
     async def create_dm(self, user_id: str) -> None:
         await self._perform_action({"action": "create_dm", "data": {"userId": user_id}})
diff --git a/trafficlight/tests/fallback_key_test.py b/trafficlight/tests/fallback_key_test.py
new file mode 100644
index 0000000..8ce9d46
--- /dev/null
+++ b/trafficlight/tests/fallback_key_test.py
@@ -0,0 +1,83 @@
+import asyncio
+import logging
+
+from nio import AsyncClient, AsyncClientConfig, SyncResponse, store
+
+from trafficlight.client_types import ElementWebStable
+from trafficlight.homerunner import HomeServer
+from trafficlight.internals.client import MatrixClient, NetworkProxyClient
+from trafficlight.internals.test import Test
+from trafficlight.server_types import SynapseDevelop
+
+
+# CLIENT_COUNT=2  REQUIRES_PROXY=true CYPRESS_BASE_URL="https://app.element.io" ./trafficlight/scripts-dev/run-localdev-setup.sh && tmux kill-server
+# Passing Test
+class FallbackKeyTest(Test):
+    def __init__(self) -> None:
+        super().__init__()
+        self._client_under_test([ElementWebStable()], "alice")
+        self._client_under_test([ElementWebStable()], "bob")
+        self._network_proxy("alice_proxy")
+        self._server_under_test(SynapseDevelop(), ["server"])
+
+    async def run(
+        self,
+        alice: MatrixClient,
+        bob: MatrixClient,
+        server: HomeServer,
+        alice_proxy: NetworkProxyClient,
+    ) -> None:
+        await alice_proxy.proxy_to(server)
+        await asyncio.gather(alice.register(alice_proxy), bob.register(server))
+        room_id = await alice.create_room("fallback test room")
+        logging.info(f"Got room-id as {room_id}")
+        await alice.invite_user(f"{bob.localpart}:{server.server_name}")
+        await bob.accept_invite()
+        # disable sync for alice, so she can't upload more device keys
+        await alice_proxy.disable_endpoint("/_matrix/client/r0/sync")
+        for i in range(60):
+            await login_and_send_message_in_room(
+                server, bob, room_id, f"Hello world {i + 1}!"
+            )
+        await alice_proxy.enable_endpoint("/_matrix/client/r0/sync")
+        # last message would have exhausted the OTKs,
+        # so we should have fallen back to the fallback key
+        await alice.verify_message_in_timeline("Hello world 60!")
+
+
+async def login_and_send_message_in_room(
+    server: HomeServer, user: MatrixClient, room_id: str, message: str
+) -> None:
+    # need to install python-olm and pip install "matrix-nio[e2e]
+    logging.info(
+        f"trying to login as @{user.localpart}:{server.server_name} with password ${user.password} and send a message in #{room_id}..."
+    )
+    user_id = f"@{user.localpart}:{server.server_name}"
+    client = AsyncClient(
+        server.cs_api,
+        user_id,
+        config=AsyncClientConfig(
+            encryption_enabled=True, store=store.SqliteMemoryStore
+        ),
+    )
+
+    # This method will be called after each sync
+    async def handle_sync(_: None) -> None:
+        # Send the message after initial sync
+        await client.room_send(
+            room_id,
+            message_type="m.room.message",
+            content={"msgtype": "m.text", "body": message},
+            ignore_unverified_devices=True,
+        )
+        # Stop syncing
+        task.cancel()
+
+    try:
+        client.add_response_callback(handle_sync, SyncResponse)
+        await client.login(user.password)
+        # sync_forever must be used for encryption to work
+        task = asyncio.create_task(client.sync_forever(timeout=30000))
+        await task
+    finally:
+        await client.close()