Senior Contract C++ / JavaScript Software Engineer Firefox (Browser Engine) is open at Mozilla (Remote France). Posted on Oct 20, 2026, and still on Mozilla’s careers page when we last checked, on Nov 14, 2026.
About 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…
The opening lines of the posting. The rest is on Mozilla’s careers page.
Hiring at Mozilla
Mozilla has 121 open roles right now, 121 of them remote. Most are in Engineering, Security and Sales & Business Development. The median advertised salary across its roles with a published range is $178K. See all its roles
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