A Firefox addon for use with the Mozilla Add-ons Builder (formerly known as FlightDeck).
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This is an addon that allows for integration between Firefox and the Mozilla Add-ons Builder (formerly known as FlightDeck).


  1. If necessary, either edit the file data/addon-config.json so that it contains the URL(s) for origins that host the Mozilla Add-ons Builder or set the extensions.addonBuilderHelper.trustedOrigins preference in about:config to a comma-delimited list of origins. The scheme, host, and port of each URL make up its "origin", meaning that the rest of the URL will be ignored when making trust decisions.

  2. All pages under a trusted origin will automatically have a mozFlightDeck object added to their window object. See below for its API.

  3. As soon as the addon is activated, an event of type addonbuilderhelperstart will be dispatched to the document.body element of every open tab.



Sends the JSON-able object request to the addon and returns a response object. For the purposes of this documentation, we will call the latter object response.

request must have at least one property, request.cmd, which is a string specifying a command to send the addon.

response has at least one boolean property, response.success, indicating whether the command executed successfully. If it is false, then response.msg is a string explaining why.

Valid command strings are:

  • isInstalled - Queries if an addon is currently installed in development mode, placing the boolean result in response.isInstalled. response.installedID will be the addon's ID.

  • uninstall - If an addon is currently installed in development mode, uninstalls it. If no addon is currently installed, this command does nothing.

  • install - Installs an addon in development mode, uninstalling any predecessor. obj.contents must be a string representing binary XPI data; due to bug 541828, corrupt values can actually crash some versions of Firefox, so be careful!

See examples/sample-web-page/index.html for example code that uses this API.


Haven't yet made Bugzilla bugs for these.

  • It's currently only possible for one addon to be "installed in development mode" at a time. Could be nice in the long-term to allow for multiple ones to be installed.

  • The Addon Builder Helper doesn't currently deal well with the case where addons raise exceptions while being installed or uninstalled in development mode.

  • Addons installed in development mode don't stay installed after Firefox restarts. Some think this is a feature, though, not a bug.

  • If the user has an addon installed via the Firefox Addon Manager and then tries installing the same addon in development mode using the Addon Builder Helper, an explosion occurs.