Senior Staff Performance Engineer, Firefox

Leads Firefox performance engineering by writing code, profiling bottlenecks, improving benchmarks, and guiding cross-functional teams. Requires 7+ years of experience, strong C++ and JavaScript skills, and expertise in performance-critical software, profiling, concurrency, and systems analysis.

About the job

Responsibilities

Write code and tests, build prototypes, and diagnose performance bottlenecks.
Profile and analyze performance issues across Firefox on Windows, Android, Linux, and macOS.
Use C++, JavaScript, Kotlin, Rust, and Python, with emphasis on C++ and JavaScript.
Educate engineering teams through code reviews, talks, tooling, and documentation.
Define and drive actionable next steps from high-level objectives.
Lead performance efforts with engineering teams across the organization.
Shape performance benchmarks and prioritize improvements.
Develop strategies for the Performance team and organization.

Requirements

BS/MS in Computer Science, Computer Engineering, or a related field.
7+ years of relevant experience.
Mastery of C++ programming and understanding of JavaScript.
Experience developing performance-critical software.
Experimental, measurement-driven approach to problem solving.
Experience debugging and analyzing performance bottlenecks with profiling tools such as VTune and Xperf.
Experience with multithreading, concurrency, disk I/O, and GPUs.
Track record of setting team goals and driving them to completion.
Experience motivating and aligning cross-functional teams.
Strong asynchronous written and verbal communication skills for distributed work.

Nice-to-haves

Familiarity with web standards or patterns.
Android or Windows application programming experience.
Solid understanding of statistics.
Experience working on a modern web browser.

Compensation and benefits

Performance-based bonus plans for eligible employees.
Medical, dental, and vision coverage.
Retirement contributions with immediate vesting.
Company wellness days, country-specific holidays, and birthday leave.
Home office stipend.
Annual professional development budget.
Well-being stipend.
Paid parental leave.
Employee referral bonus program.
Life and accidental-death-and-dismemberment insurance, disability coverage, and employee assistance programs, varying by country.