Firefox Add-ons Development Guide

To develop add-on for Firefox, you need to install the SDK and optional amo-validator. In this guide, you’re going to install both on the teracy-dev VM.

At the time of writing this guide, you’re going to install the latest SDK (v1.17) and latest amo-validator (v1.6.0). It’s expected that this guide should work with the latest SDK and amo-validator.

At the time of writing this guide, native JavaScript SDK is not ready for prime time yet. In the future, we will add the instruction here. However, as it’s a nodejs module, it’s very easy to install on the teracy-dev VM as nodejs is available by default.

First of all, make sure that the teracy-dev VM is running, if not yet, please follow the guide here at: Getting Started

Firefox Add-ons SDK Installation

This installation guide is based on


Within the teracy-dev VM with default configuration:

  • Python 2.7 is already available by default
  • Firefox is not available, so you cannot use the commands involving Firefox, for example: $ cfx run or $ cfx test

To install the SDK, the following steps need accomplishing:

  1. $ vagrant ssh if you are not ssh-ing the teracy-dev VM yet.

  2. Download the SDK

    $ cd ~/workspace/readonly
    $ wget
    $ tar -xf jetpack-sdk-latest.tar.gz

    After extracting, it’s expected that the SDK is available at ~/workspace/readonly/addon-sdk-1.17

  3. Make activate permanent

    $ sudo ln -s ~/workspace/readonly/add-on-sdk-1.17/bin/cfx /usr/local/bin/cfx

And from now on you can use $ cfx anywhere. To verify, try the command below:

$ cfx --version

And you should see the following output:

Add-on SDK 1.17 (12f7d53e8b5fc015a15fa4a30fa588e81e9e9b2e)

You can start building Firefox Add-ons now by following the instruction at: Validator Installation

To publish the add-ons on AMO, it requires review process and amo-validator is provided to help you to spot some common problems as early as possible.

amo-validator is available as Python package at:

To install amo-validator, you need to add amo-validator and fastchardet to python global system packages.

  1. Open vagrant_config_override.js and override the default python configuration as follows:



    At the time of this writing, fastchardet is required by amo-validator but not included in, that’s the reason why you need to add it in the configuration above.

  2. Provision the teracy-dev VM

    $ vagrant provision

    After that, addon-validator should be available. Try the following commands to verify:

    $ vagrant ssh
    $ addon-validator

    And you should see the following output:

    usage: addon-validator [-h]
                           [-t {theme,multi,dictionary,extension,webapp,search,any,languagepack}]
                           [-o {text,json}] [-v] [--boring] [--determined]
                           [--approved_applications APPROVED_APPLICATIONS]
                           [--target-maxversion TARGET_MAXVERSION]
                           [--target-minversion TARGET_MINVERSION]
                           [--for-appversions FOR_APPVERSIONS] [--timeout TIMEOUT]
    addon-validator: error: too few arguments

From now on, you can use addon-validator anywhere to check for the Firefox add-ons before submitting to AMO. This will save us a lot of time when preparing for AMO publishing.