← All roles

Senior Contract C++ / JavaScript Software Engineer Firefox (Browser Engine)

Mozilla· Firefox
Apply on company site
RemoteNot specifiedPosted 6d ago

About the role

Role focused on improving Session History quality in Firefox's DOM Core by writing and fixing tests to increase coverage and Gecko correctness, with emphasis on test automation and collaboration through code reviews.

Responsibilities

  • Write Web-Platform tests to improve the coverage, and Gecko mochitests as needed
  • Fix the problems and pass the tests to improve the Gecko correctness
  • Work through code review with the relevant Gecko module owners and iterate to landing

Qualifications

  • Substantial experience in a browser-engine codebase or in automating for a browser-engine, ideally Firefox/Gecko
  • Solid Javascript and applying that language skill to write automated tests
  • Proficiency in and experience developing software in C++
  • Strong debugging skills in a mature large codebase
  • Comfort working in the open: public bugs, code review, and upstream landing

Skills

Required:Web-Platform testingJavaScriptC++Debugging
Last updated Oct 21, 2026. Interested? Apply on the company site.

About Mozilla

Internet for people, not profit

Mozilla is the not-for-profit behind the lightning fast Firefox browser. We put people over profit to give everyone more power online.

BrowserInternetNot-for-profitFirefox
Company profileWebsite

More open roles at Mozilla