diff --git a/backend/googlecloudstorage/googlecloudstorage.go b/backend/googlecloudstorage/googlecloudstorage.go
index 449e371bc..3c9062be7 100644
--- a/backend/googlecloudstorage/googlecloudstorage.go
+++ b/backend/googlecloudstorage/googlecloudstorage.go
@@ -346,9 +346,26 @@ can't check the size and hash but the file contents will be decompressed.
 			Advanced: true,
 			Default:  false,
 		}, {
-			Name:     "endpoint",
-			Help:     "Endpoint for the service.\n\nLeave blank normally.",
+			Name: "endpoint",
+			Help: `Custom endpoint for the storage API. Leave blank to use the provider default.
+
+When using a custom endpoint that includes a subpath (e.g. example.org/custom/endpoint),
+the subpath will be ignored during upload operations due to a limitation in the
+underlying Google API Go client library.
+Download and listing operations will work correctly with the full endpoint path.
+If you require subpath support for uploads, avoid using subpaths in your custom
+endpoint configuration.`,
 			Advanced: true,
+			Examples: []fs.OptionExample{{
+				Value: "storage.example.org",
+				Help:  "Specify a custom endpoint",
+			}, {
+				Value: "storage.example.org:4443",
+				Help:  "Specifying a custom endpoint with port",
+			}, {
+				Value: "storage.example.org:4443/gcs/api",
+				Help:  "Specifying a subpath, see the note, uploads won't use the custom path!",
+			}},
 		}, {
 			Name:     config.ConfigEncoding,
 			Help:     config.ConfigEncodingHelp,