As all mobile developers should know Weinre is the best thing to have happened to mankind since American Idol got cancelled. It allows you to connect the Chrome Debugger Tools to a remote mobile device and use awesomeness like Element inspection, CSS manipulation and javascript execution to do debugging on steroids. No more alert style debugging your mobile websites. Speed++.

On the other hand Firefox OS, the best thing to have happened since the invention of in-plane WiFi (guess where I’m writing this blog post), lacks a proper way to debug applications after deploying them to your shiny new phone.

By combining these two facts, plus given that the Firefox OS UI layer is completely written in web standards, it’s only natural that we at Telenor Comoyo (ok, ok, Kevin Grandon came up with the original idea) started hacking on superawesomeincrediblegreat integration of Weinre and Firefox OS. That means: live viewing and manipulating your app markup; live editing of styles and live code injection. All from your desktop and directly accessible on your developer phone. Now try that on any other mobile platform. But Jan, how do we know that it actually works? Well dear folks, here is a video:

Great, I want it!

Sure, here’s how you’ll get started:

  1. Install node.js
  2. Install Weinre via npm install -g weinre
  3. Start Weinre via weinre --boundHost -all- --httpPort 9090
  4. Check out the Comoyo build Gaia, the UI library for Firefox OS (git clone git//
  5. Build Gaia with the Weinre extension: WEINRE=your.internal.ip:9090 make
  6. Grab the Firefox OS system
  7. Now start the emulator from your Gaia directory: f.e. on OS/X: /Applications/ -profile $PWD/profile
  8. Go to the Weinre debug interface on your workstation and see the magic happening.

When you’re ready to debug an application, add the following line to your index.html and restart the emulator:

<script src="shared/js/weinre_app.js"></script>

Lessons learned

For 15 years we built software to develop, design and debug on the web. It’s incredible to see that we can leverage all this existing technology and integrate them into our Firefox OS build chain with hardly any effort. I you had any doubt whether Firefox OS was the number one choice for developers, this is the moment for you to reconsider.

This debugging process has also been written up by Mozilla

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