diff --git a/pusher/src/Controller/MapController.ts b/pusher/src/Controller/MapController.ts
index 7f76ff9e..64d04a09 100644
--- a/pusher/src/Controller/MapController.ts
+++ b/pusher/src/Controller/MapController.ts
@@ -53,6 +53,7 @@ export class MapController extends BaseController {
                 const mapUrl = roomUrl.protocol + "//" + match[1];
 
                 res.writeStatus("200 OK");
+                res.writeHeader("Content-type", "application/json");
                 this.addCorsHeaders(res);
                 res.end(
                     JSON.stringify({