diff --git a/pykat/testing/web/web_interface.py b/pykat/testing/web/web_interface.py
index f029bc09d1dfa89a8a8ba2443be8fdc4018a6f73..63025d74225a4509528f5fb595315c16650d1632 100644
--- a/pykat/testing/web/web_interface.py
+++ b/pykat/testing/web/web_interface.py
@@ -407,7 +407,7 @@ def __finesse_start_test(git_commit, kats, nobuild=False):
     finally:
         schedule_lock.release()
     
-    return {state:'OK'}
+    return jsonify(dict(state='OK'))
         
 @app.route('/finesse/get_tests', methods=["POST"])
 def finesse_get_tests():