Contract Software Engineer - DOM Core Firefox/Gecko at Mozilla in Remote France; Remote Germany; Remote UK
- Company: Mozilla
- Location: Remote France; Remote Germany; Remote UK
- Posted: Sep 23, 2026
- Type: Contract
- Experience: 6+ years
Overview
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. Write Web-Platform tests to improve the coverage, and Gecko mochitests as needed
Job description
- 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
Requirements
- 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.
- Prior contributions to Gecko or another major browser engine.
- Familiarity with web standards and Web Platform Tests.
Skills
Required
- Javascript
- C++
- Debugging
- Automated testing
- Browser-engine codebase experience