Mozilla
Senior Contract C++ / JavaScript Software Engineer Firefox (Browser Engine)
Be an Early Applicant
Improve Firefox Gecko’s Session History reliability by expanding Web Platform and Gecko mochitest coverage, debugging failures, fixing correctness issues, and landing changes through code review. The role requires substantial browser-engine experience, strong C++ and JavaScript skills, and comfort working with public bugs, module owners, and upstream development processes.
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
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.
- Prior contributions to Gecko or another major browser engine.
- Familiarity with web standards and Web Platform Tests.
Similar Jobs
Security • Cybersecurity
Retain and expand approximately 100 existing customer accounts through consultative selling, renewals, upsells, cross-sells, account planning, partner engagement, and pipeline development. The role manages complex enterprise sales cycles, presents to technical and executive stakeholders, maintains accurate Salesforce records and forecasts, collaborates cross-functionally, and meets revenue targets.
Top Skills:
Cybersecurity SolutionsEnterprise SoftwareSalesforce
Cloud • Computer Vision • Information Technology • Sales • Security • Cybersecurity
Conduct incident response engagements and intrusion investigations for major organizations. Hunt for threat actors across large datasets, perform host and network forensics across Windows, macOS, and Linux, analyze malware and network activity, and support remediation planning. Prepare reports, presentations, recommendations, and findings for customers, regulators, executives, and legal counsel while collaborating with project leadership and internal teams.
Top Skills:
AIAWSAzureBro/ZeekGCPLinuxmacOSSuricataWindows
Cloud • Information Technology • Productivity • Security • Software • App development • Automation
Own EMEA Mid-Market sales readiness by identifying capability gaps, adapting global enablement programs, and delivering onboarding, coaching, facilitation, and manager reinforcement. Strengthen value-based selling and MEDDPICC execution, improve tool and AI proficiency, and measure impact through ramp time, pipeline quality, conversion, sales-cycle efficiency, and expansion metrics.
Top Skills:
AIGongLinkedin Sales NavigatorOutreachSalesforceSalesloft
What you need to know about the London Tech Scene
London isn't just a hub for established businesses; it's also a nursery for innovation. Boasting one of the most recognized fintech ecosystems in Europe, attracting billions in investments each year, London's success has made it a go-to destination for startups looking to make their mark. Top U.K. companies like Hoptin, Moneybox and Marshmallow have already made the city their base — yet fintech is just the beginning. From healthtech to renewable energy to cybersecurity and beyond, the city's startups are breaking new ground across a range of industries.
