diff --git a/changelog.d/4289.feature b/changelog.d/4289.feature
new file mode 100644
index 0000000000000000000000000000000000000000..4d53bd22c38cb9fdf331aab138a11ef17ffa43c9
--- /dev/null
+++ b/changelog.d/4289.feature
@@ -0,0 +1 @@
+Add a welcome page for the client API port. Credit to @krombel!
\ No newline at end of file
diff --git a/synapse/app/homeserver.py b/synapse/app/homeserver.py
index 3e4dea2f196a3e4c3763175f8a234b8d89cd61df..e433c6655831861b65296549ade5efeea2b584d9 100755
--- a/synapse/app/homeserver.py
+++ b/synapse/app/homeserver.py
@@ -137,8 +137,11 @@ class SynapseHomeServer(HomeServer):
handler = handler_cls(config, module_api)
resources[path] = AdditionalResource(self, handler.handle_request)
+ # try to find something useful to redirect '/' to
if WEB_CLIENT_PREFIX in resources:
root_resource = RootRedirect(WEB_CLIENT_PREFIX)
+ elif STATIC_PREFIX in resources:
+ root_resource = RootRedirect(STATIC_PREFIX)
else:
root_resource = NoResource()
diff --git a/synapse/static/index.html b/synapse/static/index.html
new file mode 100644
index 0000000000000000000000000000000000000000..d6642399837d24b903bb97017fc215b45735251f
--- /dev/null
+++ b/synapse/static/index.html
@@ -0,0 +1,26 @@
+<html>
+ <head>
+ <title>Synapse is running</title>
+ <style>
+ body {
+ width: 30em;
+ margin: 0 auto;
+ font-family: Tahoma, Verdana, Arial, sans-serif;
+ }
+ h1 {
+ text-align: center;
+ }
+ </style>
+ </head>
+ <body>
+ <h1>Synapse is running</h1>
+ <p>Congratulations!</p>
+ <p>Your Synapse server is listening on this port and is ready for messages.</p>
+ <p>To use this server you'll need a client - e.g. one of
+ <a href="https://matrix.org/docs/projects/try-matrix-now.html#clients">this list of Matrix clients</a>.</p>
+ <p>You can find (federated) rooms that might be of interest to you on
+ <a href="https://view.matrix.org/">view.matrix.org</a>.</p>
+ <p>Or you just start creating your own rooms with your friends.</p>
+ <p>Welcome to the Matrix universe :)</p>
+ </body>
+</html>