Salary not listed
Senior Contract C++ / JavaScript Software Engineer Firefox (Browser Engine)
OtherWorkplace — unknown
Published on 2026-10-20
These details were extracted automatically from the original listing. They may not be complete or fully up to date — it's worth checking the original job post.
About this role
Improve Firefox Gecko’s Session History correctness and test coverage. The work involves writing Web Platform Tests and Gecko mochitests, fixing issues, and collaborating with module owners through code review and upstream landing.
About the company
Mozilla builds open-source products and technologies, including Firefox, that prioritize privacy, security, and an open internet.
The team
Firefox DOM Core team
Stack
C++JavaScriptGeckoFirefoxWeb Platform Testsmochitests
What you'll do
- Write Web Platform Tests and Gecko mochitests to expand coverage
- Fix Gecko issues and ensure tests pass
- Work with Gecko module owners through code review and landing
What we're looking for
- Substantial experience with a browser-engine codebase or browser-engine test automation
- Strong JavaScript skills for automated testing
- C++ software development experience
- Strong debugging skills in a large, mature codebase
- Comfort working in public bug trackers, code review, and upstream contributions
Nice to have
- Contributions to Gecko or another major browser engine
- Familiarity with web standards and Web Platform Tests