diff --git a/lib/routes/api/applications.js b/lib/routes/api/applications.js
index 6020bec..50e0d3a 100644
--- a/lib/routes/api/applications.js
+++ b/lib/routes/api/applications.js
@@ -101,6 +101,20 @@ async function validateUpdate(req, sid) {
   if (req.body.call_status_hook && typeof req.body.call_hook !== 'object') {
     throw new DbErrorBadRequest('\'call_status_hook\' must be an object when updating an application');
   }
+
+  let urlError;
+  if (req.body.call_hook) {
+    urlError = await isInvalidUrl(req.body.call_hook.url);
+    if (urlError) {
+      throw new DbErrorBadRequest(`call_hook ${urlError}`);
+    }
+  }
+  if (req.body.call_status_hook) {
+    urlError = await isInvalidUrl(req.body.call_status_hook.url);
+    if (urlError) {
+      throw new DbErrorBadRequest(`call_status_hook ${urlError}`);
+    }
+  }
 }
 
 async function validateDelete(req, sid) {
@@ -290,9 +304,6 @@ router.put('/:sid', async(req, res) => {
           obj[`${prop}_sid`] = sid;
         }
       }
-      else {
-        obj[`${prop}_sid`] = null;
-      }
       delete obj[prop];
     }