Support for extensions using XUL/XPCOM or the Add-on SDK was removed in Firefox 57, released November 2017. As there is no supported version of Firefox enabling these technologies, this page will be removed by December 2020.

Add-ons using the techniques described in this document are considered a legacy technology in Firefox. Don't use these techniques to develop new add-ons. Use WebExtensions instead. If you maintain an add-on which uses the techniques described here, consider migrating it to use WebExtensions.

Starting from Firefox 53, no new legacy add-ons will be accepted on (AMO) for desktop Firefox and Firefox for Android.

Starting from Firefox 57, only extensions developed using WebExtensions APIs will be supported on Desktop Firefox and Firefox for Android.

Even before Firefox 57, changes coming up in the Firefox platform will break many legacy extensions. These changes include multiprocess Firefox (e10s), sandboxing, and multiple content processes. Legacy extensions that are affected by these changes should migrate to use WebExtensions APIs if they can. See the "Compatibility Milestones" document for more information.

A wiki page containing resources, migration paths, office hours, and more, is available to help developers transition to the new technologies.



Display transient, toaster-style desktop messages to the user.


This API supports desktop notifications on Windows, OS X using Growl (and Notification Center as of OS X 10.9 Mavericks), and Linux using libnotify.

Here's a typical example. When the message is clicked, a string is logged to the console.

var notifications = require("sdk/notifications");
  title: "Jabberwocky",
  text: "'Twas brillig, and the slithy toves",
  data: "did gyre and gimble in the wabe",
  onClick: function (data) {
    // console.log( would produce the same result.

This one displays an icon that's stored in the add-on's data directory. See the self module documentation for more information.

var notifications = require("sdk/notifications");
var self = require("sdk/self");
var myIconURL ="myIcon.png");

  text: "I have an icon!",
  iconURL: myIconURL

From Firefox 34, you can use "./myIcon.png" as an alias for"myIcon.png"). So you can rewrite the above code like this:

var notifications = require("sdk/notifications");
var myIconURL = "./myIcon.png";

  text: "I have an icon!",
  iconURL: myIconURL

This module depends on the underlying system's notification service. If the user's system does not support desktop notifications or if its notifications service is not running:

  • if Firefox was started normally, notifications are logged to Firefox's error console
  • if the user launched Firefox from the command line, notifications are logged to the terminal.




Displays a transient notification to the user.


options : object
Optional options:

Name Type  
title string

A string to display as the message's title.

text string

A string to display as the body of the message.

iconURL string

The URL of an icon to display inside the message. It may be a remote URL, a data URI, or a URL returned by the self module.

onClick function

A function to be called when the user clicks the message. It will be passed the value of data.

data string

A string that will be passed to onClick.