diff --git a/routes/message.js b/routes/message.js
index f002277..f5b1eac 100644
--- a/routes/message.js
+++ b/routes/message.js
@@ -14,6 +14,7 @@ router.get('/:guid', function (req, res) {
       return res.status(404).send(`No record found for ${guid}.`);
     }
     else {
+      res.set('Content-Type', 'application/activity+json');
       res.json(JSON.parse(result.message));
     }
   }