diff --git a/robot-server/robot_server/client_data/router.py b/robot-server/robot_server/client_data/router.py
index 35ec8c6e06c4..a70e94522aed 100644
--- a/robot-server/robot_server/client_data/router.py
+++ b/robot-server/robot_server/client_data/router.py
@@ -13,6 +13,10 @@
 from robot_server.errors.error_responses import ErrorBody, ErrorDetails
 from robot_server.service.json_api.request import RequestModel
 from robot_server.service.json_api.response import SimpleBody, SimpleEmptyBody
+from robot_server.service.notifications.publishers.client_data_publisher import (
+    ClientDataPublisher,
+    get_client_data_publisher,
+)
 
 router = fastapi.APIRouter()
 
@@ -62,9 +66,13 @@ class ClientDataKeyDoesNotExist(ErrorDetails):
 async def put_client_data(  # noqa: D103
     key: Key,
     request_body: RequestModel[ClientData],
-    store: ClientDataStore = fastapi.Depends(get_client_data_store),
+    store: Annotated[ClientDataStore, fastapi.Depends(get_client_data_store)],
+    client_data_publisher: Annotated[
+        ClientDataPublisher, fastapi.Depends(get_client_data_publisher)
+    ],
 ) -> SimpleBody[ClientData]:
     store.put(key, request_body.data)
+    await client_data_publisher.publish_client_data(key)
     return SimpleBody.construct(data=store.get(key))
 
 
@@ -104,7 +112,10 @@ async def get_client_data(  # noqa: D103
 )
 async def delete_client_data(  # noqa: D103
     key: Key,
-    store: ClientDataStore = fastapi.Depends(get_client_data_store),
+    store: Annotated[ClientDataStore, fastapi.Depends(get_client_data_store)],
+    client_data_publisher: Annotated[
+        ClientDataPublisher, fastapi.Depends(get_client_data_publisher)
+    ],
 ) -> SimpleEmptyBody:
     try:
         store.delete(key)
@@ -113,6 +124,7 @@ async def delete_client_data(  # noqa: D103
             fastapi.status.HTTP_404_NOT_FOUND
         ) from e
     else:
+        await client_data_publisher.publish_client_data(key)
         return SimpleEmptyBody.construct()
 
 
@@ -125,4 +137,8 @@ async def delete_all_client_data(  # noqa: D103
     store: ClientDataStore = fastapi.Depends(get_client_data_store),
 ) -> SimpleEmptyBody:
     store.delete_all()
+    # FIXME(mm, 2024-07-24): We need to notify MQTT subscribers to
+    # `robot-server/client/{key}` (for all values of `key`).
+    # We can do it like RunsPublisher and drive the notifications from the underlying
+    # store instead of driving notifications from these endpoint functions.
     return SimpleEmptyBody.construct()
diff --git a/robot-server/robot_server/service/notifications/publishers/client_data_publisher.py b/robot-server/robot_server/service/notifications/publishers/client_data_publisher.py
new file mode 100644
index 000000000000..77225368a353
--- /dev/null
+++ b/robot-server/robot_server/service/notifications/publishers/client_data_publisher.py
@@ -0,0 +1,29 @@
+from typing import Annotated
+import fastapi
+from robot_server.service.notifications import topics
+from robot_server.service.notifications.notification_client import (
+    NotificationClient,
+    get_notification_client,
+)
+
+
+class ClientDataPublisher:
+    """Publishes clientData topics."""
+
+    def __init__(self, client: NotificationClient) -> None:
+        self._client = client
+
+    async def publish_client_data(self, client_data_key: str) -> None:
+        """Publish the equivalent of `GET /clientData/{key}`."""
+        await self._client.publish_advise_refetch_async(
+            topics.client_data(client_data_key)
+        )
+
+
+async def get_client_data_publisher(
+    notification_client: Annotated[
+        NotificationClient, fastapi.Depends(get_notification_client)
+    ],
+) -> ClientDataPublisher:
+    """Return a ClientDataPublisher for use by FastAPI endpoints."""
+    return ClientDataPublisher(notification_client)