Mozilla Logo

Mozilla

Contract Software Engineer - DOM Core Firefox/Gecko

Posted 3 Days Ago
Be an Early Applicant
Remote
Hiring Remotely in UK
Senior level
Remote
Hiring Remotely in UK
Senior level
Improve Firefox Gecko’s Session History health by writing Web Platform Tests and Gecko mochitests, fixing test failures and code issues, debugging a mature browser-engine codebase, and collaborating through code review and upstream landing.
The summary above was generated by AI
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.

Similar Jobs

An Hour Ago
Remote or Hybrid
UK
Mid level
Mid level
HR Tech • Information Technology • Professional Services • Sales • Software
Provide consultative guidance on UK Payroll configuration, system design, integrations, implementation readiness, and best practices. Troubleshoot complex payroll issues, translate legislation into system recommendations, and support customer adoption. Partner with Product and R&D on feature validation, beta testing, roadmap input, and functionality improvements. Develop scalable onboarding frameworks, lead knowledge sharing, and act as the payroll subject matter expert across Customer Success.
Top Skills: HrisHris And Finance System IntegrationsPayroll AutomationPayroll PlatformsSaaSUk Payroll
3 Hours Ago
Remote or Hybrid
Senior level
Senior level
Artificial Intelligence • Cloud • HR Tech • Information Technology • Productivity • Software • Automation
Build and deploy production-grade LLM applications spanning backend services, data orchestration, vector search, and front-end integrations. Work directly with strategic customers in agile sprints, integrate legacy systems, create reusable AI libraries and scaffolds, and influence platform strategy through field-tested solutions. Lead implementations from concept to production while ensuring scalability, security, observability, and performance.
Top Skills: AngularAWSAzureCi/CdContainersGCPGraphQLInfrastructure As CodeJavaLangchainLlmsNode.jsPrompt ChainingPythonReactRestSalesforceSemantic KernelServicenowVector DatabasesVector Search
3 Hours Ago
Easy Apply
Remote
United Kingdom
Easy Apply
Expert/Leader
Expert/Leader
Cloud • Security • Software • Cybersecurity • Automation
Leads technical direction for GitLab’s Core DevOps services, covering CI, CD, planning, and source control. Defines architecture, quality metrics, migration strategies, and technical roadmaps; addresses systemic risk and complex design decisions; prototypes and writes code when needed; partners with Infrastructure, Security, SRE, and Product; adopts AI capabilities; mentors senior engineers; supports incident response and senior technical hiring.
Top Skills: Agentic FrameworksAIAutonomous WorkflowsCi/CdDevOpsDistributed SystemsFault ToleranceGitlabHuman-In-The-Loop ControlsLarge Language ModelsMachine LearningMulti-Tenant SystemsObservabilityResponsible Ai

What you need to know about the Bristol Tech Scene

Along with Gloucester, Swindon and Bath, Bristol is part of the "Silicon Gorge" tech hub, a region in the U.K. renowned for its high-tech and research-driven industries, with a particular emphasis on sustainability and reducing environmental impact. As the European Green Capital, Bristol is home to 25,000 cleantech companies, including Baker Hughes and unicorn Ovo Energy. The city has committed to achieving net-zero emissions within the next decade.

Sign up now Access later

Create Free Account

Please log in or sign up to report this job.

Create Free Account