diff --git a/api/client-server/definitions/room_event_filter.yaml b/api/client-server/definitions/room_event_filter.yaml
index a3bb6852..7d9184b5 100644
--- a/api/client-server/definitions/room_event_filter.yaml
+++ b/api/client-server/definitions/room_event_filter.yaml
@@ -28,4 +28,8 @@ properties:
     items:
       type: string
     type: array
+  contains_url:
+    type: boolean
+    description: If ``true``, includes only events with a url key in their content. If
+      ``false``, excludes those events.
 type: object
diff --git a/api/client-server/message_pagination.yaml b/api/client-server/message_pagination.yaml
index 853e0ec3..005b8fb3 100644
--- a/api/client-server/message_pagination.yaml
+++ b/api/client-server/message_pagination.yaml
@@ -75,6 +75,13 @@ paths:
           description: |-
             The maximum number of events to return. Default: 10.
           x-example: "3"
+        - in: query
+          type: string
+          name: filter
+          description: |-
+            A JSON RoomEventFilter to filter returned events with.
+          x-example: |-
+            {"contains_url":true}
       responses:
         200:
           description: A list of messages with a new token to request more.
diff --git a/changelogs/client_server.rst b/changelogs/client_server.rst
index d7384e31..ec74bda9 100644
--- a/changelogs/client_server.rst
+++ b/changelogs/client_server.rst
@@ -35,6 +35,10 @@
   - Add top-level ``account_data`` key to the responses to ``GET /sync`` and
     ``GET /initialSync``
     (`#380 <https://github.com/matrix-org/matrix-doc/pull/380>`_).
+  - Add ``contains_url`` option to ``RoomEventFilter``.
+    (`#390 <https://github.com/matrix-org/matrix-doc/pull/390>`_).
+  - Add ``filter`` optional query param to ``/messages``
+    (`#390 <https://github.com/matrix-org/matrix-doc/pull/390>`_).
 
 r0.2.0
 ======