diff --git a/changelogs/client_server/newsfragments/1638.feature b/changelogs/client_server/newsfragments/1638.feature
new file mode 100644
index 00000000..a90cc4dd
--- /dev/null
+++ b/changelogs/client_server/newsfragments/1638.feature
@@ -0,0 +1 @@
+Add a note to the `/publicRooms` API that the server name is case sensitive. 
diff --git a/data/api/client-server/list_public_rooms.yaml b/data/api/client-server/list_public_rooms.yaml
index ba816b06..678f52ad 100644
--- a/data/api/client-server/list_public_rooms.yaml
+++ b/data/api/client-server/list_public_rooms.yaml
@@ -154,7 +154,7 @@ paths:
           name: server
           description: |-
             The server to fetch the public room lists from. Defaults to the
-            local server.
+            local server. Case sensitive.
           schema:
             type: string
       responses:
@@ -181,7 +181,7 @@ paths:
           name: server
           description: |-
             The server to fetch the public room lists from. Defaults to the
-            local server.
+            local server. Case sensitive.
           schema:
             type: string
       requestBody: