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Staff Firefox Performance Engineer

Mozilla· Firefox
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Remote$163k - $218kfull-timePosted 1w ago

About the role

Mozilla Firefox Performance team engineer focused on delivering the fastest browser by identifying and fixing performance bottlenecks across Windows, Android, Linux, and macOS, with a distributed, open-working environment.

Responsibilities

  • Write code and tests, build prototypes, tackle problems, profile and analyze performance bottlenecks
  • Learn about a wide variety of problems and solutions across a large, complex, and evolving codebase
  • Use several programming languages (e.g., C++, JavaScript, Kotlin, Rust, Python) and techniques to fix performance issues, with an emphasis on C++ and JavaScript
  • Help to educate engineers on other teams about writing more performant code through code reviews, giving talks, implementing tooling, and/or writing documentation
  • Break down complex performance problems into actionable next steps and drive them to completion
  • Partner with engineering teams across the organization to support performance efforts, and lead them within your area
  • Contribute to the direction of performance benchmarks and help prioritize the improvements that matter most
  • Own the performance of a significant area of the browser end to end, and contribute to the Performance team's technical roadmap
  • Work with driven, committed team members to help bring the Open Web to millions of people

Qualifications

  • BS/MS in CS or CE, and 5+ years of relevant experience
  • Deep proficiency in C++
  • Working proficiency in JavaScript
  • You have proven experience developing performance-critical software
  • You take an experimental and measured approach to solving problems (measurement, and using experiments to diagnose an issue or prove out a solution)
  • Proven skill in debugging and analyzing performance bottlenecks, and using profiling tools to diagnose and fix issues (VTune, Xperf, other sampling based profilers)
  • Experience with at least one of: multithreading and concurrency, disk I/O, or GPU work
  • Track record of driving projects to completion, including work spanning more than one engineer
  • Experience collaborating with engineers on other teams to deliver shared goals
  • An interest and ability to work in a distributed team (good asynchronous written communication skills as well as good verbal communication skills)

Skills

Required:C++JavaScriptPerformance profilingMultithreading / Concurrency

Benefits

  • Generous performance-based bonus plans to all eligible employees - we share in our success as one team
  • Rich medical, dental, and vision coverage
  • Generous retirement contributions with 100% immediate vesting
  • Quarterly all-company wellness days where everyone takes a pause together
  • Country specific holidays plus a day off for your birthday
  • One-time home office stipend
  • Annual professional development budget
  • Quarterly well-being stipend
  • Considerable paid parental leave
  • Employee referral bonus program
  • Other benefits (life/AD&D, disability, EAP, etc. - varies by country)
Last updated Oct 14, 2026. Interested? Apply on the company site.

About Mozilla

Internet for people, not profit

Mozilla is the not-for-profit behind the lightning fast Firefox browser. We put people over profit to give everyone more power online.

BrowserInternetNot-for-profitFirefox
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