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Contract Software Engineer - DOM Core Firefox/Gecko

Mozilla

Remote · Remote · Posted Sep 22, 2026

At a glance

Workplace
Remote
Location
Remote

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 coverage and fix tests or problems to improve 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.

Preferred qualifications

  • Prior contributions to Gecko or another major browser engine.
  • Familiarity with web standards and Web Platform Tests.

Skills

  • JavaScript
  • C++
  • Web-Platform Tests
  • Gecko Mochitests

Mozilla

Contract Software Engineer - DOM Core Firefox/Gecko

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