Senior Performance Engineer — Shape a Blazing Open Web

Mozilla; Toronto; On-site; CAD 165,000 - 220,000; Full time

Benefits offered by this job

Generous bonus plans

Medical, dental, and vision coverage

Retirement contributions with vesting

Home office stipend

Professional development budget

Parental leave

Employee referral bonus

Well-being stipend

Life/AD&D, disability, EAP

Job summary

Mozilla seeks an experienced performance engineer to optimize the Firefox browser across Windows, Android, Linux, and macOS. You will tackle bottlenecks, write fast code, and collaborate with distributed teams to improve overall speed and reliability for users.

Expect to work with C++, JavaScript, and profiling tools, contributing to performance strategies and education across teams. This role is based in Canada with a strong focus on browser performance.

Qualifications

• BS/MS in CS/CE with 7+ years of relevant experience.
• Mastered understanding of C++ and proficiency in JavaScript.
• Proven experience in performance critical software and profiling.

Responsibilities

• Write code and tests, build prototypes, and profile bottlenecks.
• Learn across a large, evolving codebase and complex problems.
• Use C++, JavaScript, Kotlin, Rust, Python to fix performance issues.
• Educate engineers through reviews, talks, tooling, and docs.
• Define and drive actionable next steps from high level objectives.
• Collaborate with teams to lead performance efforts.
• Shape future performance benchmarks and improvements.

Skills

C++ proficiency

JavaScript proficiency

Performance profiling

Multithreading

Distributed systems

Debugging skills

Asynchronous communication

Education

BS/MS in CS/CE

Tools

VTune

Xperf

Profilers

Job description

Mozilla seeks an experienced performance engineer to optimize the Firefox browser across Windows, Android, Linux, and macOS. You will tackle bottlenecks, write fast code, and collaborate with distributed teams to improve overall speed and reliability for users.

Expect to work with C++, JavaScript, and profiling tools, contributing to performance strategies and education across teams. This role is based in Canada with a strong focus on browser performance.