This role has closed. mozilla has taken the posting down.
hirly last saw it live on 23 September 2026. See similar open roles below, or browse all Software Engineer jobs.
mozilla
Contract Software Engineer - DOM Core Firefox/Gecko
Location unstated
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hirly's read of this role
- Role family
- Engineering
- Seniority
- Mid level
- Work mode
- On-site / unstated
- First seen by hirly
- 23 Sept 2026
Derived automatically from the posting.
the posting
The role
You will help the Firefox DOM Core team improve the health of the Session History area. You will write tests to improve the coverage; you will fix tests and/or problems to improve the Gecko correctness.
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
Definition of done
Improved Session History test coverage and code correctness in Gecko, measured by passed test cases, allowing the team’s senior engineers to focus on security, performance and strategic projects.
Required 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 larget codebase.
Comfort working in the open: public bugs, code review, and upstream landing.
Preferred
Prior contributions to Gecko or another major browser engine.
Familiarity with web standards and Web Platform Tests.
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