Timothy Guan‑tin Chien·@timdream

Mozilla Firefox OS 2011‑​2015

My involvement in the Firefox OS project lasts a little more than four years, out of its five-year existence. I started as a junior engineer and moved up to became an engineering manager, leading a front-end team.

As a front-end engineer, I was super excited to join the project and the company. I wholeheartedly believed Firefox OS could allow Mozilla to have a say in the Mobile Web, thus continue to project its influence over the Web Platform.

I got started immediately with the front-end code base and lay out the foundations. I worked as hard as I could, improving what I could think of everywhere, tried to stay connected with the rest of the team even with the time zone difference. In the end, I unintentionally kept the title of top committers of the repository.

Commit timeline
My commit counts, compared to overall project activities. Extracted from GitHub.

I’ve also hired the Taipei front-end team from scratch. Eventually, the front-end team in Taipei represented one-third of the front-end engineering. Many of the hires were great engineers, together we overhauled the Settings app, the Keyboard app and keeping its 60 fps performance. I was particularly proud when the bootstrap sequence of the phone, in the “System app”, was eventually retrofitted into a Promise chain.

Firefox OS Keyboard
The fully functional touch keypad still works in a regular browser, try it out on a smartphone!

The phone finally shipped in Central- and South-America countries, Europe, India, and Japan, although Firefox OS never got the traction the company had hoped. Eager for commercial success, the project moved from one partner from another and tried to jam every hardware-centric features the partner had asked. Regretfully, we never had time to pause and re-orientate on overall user experience.

Eventually, Firefox OS was discontinued. The engineering group in Taipei then became its cost center, and I took the team to work on desktop Firefox features.


Many of my team members, with a few colleagues, have been continuing working on “KaiOS”, a commercial fork of Firefox OS.