diff --git a/src/groups.js b/src/groups.js
new file mode 100644
index 0000000000..9627fcc1cd
--- /dev/null
+++ b/src/groups.js
@@ -0,0 +1,27 @@
+/*
+Copyright 2017 New Vector Ltd
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import PropTypes from 'prop-types';
+
+export const GroupMemberType = PropTypes.shape({
+    userId: PropTypes.string.isRequired,
+});
+
+export function groupMemberFromApiObject(apiObject) {
+    return {
+        userId: apiObject.user_id,
+    }
+}