diff --git a/apps/system/js/sync_manager.js b/apps/system/js/sync_manager.js
index 0120e5697bb2..3b9059797d86 100644
--- a/apps/system/js/sync_manager.js
+++ b/apps/system/js/sync_manager.js
@@ -610,7 +610,10 @@
       return new Promise((resolve, reject) => {
         navigator.mozApps.getSelf().onsuccess = event => {
           var app = event.target.result;
-          app.connect(SYNC_REQUEST_IAC_KEYWORD).then(ports => {
+          app.connect(SYNC_REQUEST_IAC_KEYWORD, {
+            // For now we only allow one synchronizer app.
+            pageURLs: 'app://sync.gaiamobile.org'
+          }).then(ports => {
             if (!ports || !ports.length) {
               return reject();
             }
diff --git a/tv_apps/smart-system/js/sync_manager.js b/tv_apps/smart-system/js/sync_manager.js
index 0f975381861a..40f1aca4e18d 100644
--- a/tv_apps/smart-system/js/sync_manager.js
+++ b/tv_apps/smart-system/js/sync_manager.js
@@ -778,7 +778,10 @@
       return new Promise((resolve, reject) => {
         navigator.mozApps.getSelf().onsuccess = event => {
           var app = event.target.result;
-          app.connect(SYNC_REQUEST_IAC_KEYWORD).then(ports => {
+          app.connect(SYNC_REQUEST_IAC_KEYWORD, {
+            // For now we only allow one synchronizer app.
+            pageURLs: 'app://sync.gaiamobile.org'
+          }).then(ports => {
             if (!ports || !ports.length) {
               return reject();
             }