Mozilla · 3 months ago
Senior Software Engineer, Firefox Performance
United States
Full-time
Remote
Senior Level
5+ years expMozilla Corporation is a non-profit-backed technology company known for its pioneering brands like Firefox. The Senior Software Engineer for Firefox Performance will focus on optimizing the browser's speed and performance by writing code, analyzing bottlenecks, and educating other engineers on performance best practices.
Browser ExtensionsInternetOpen SourceSoftwareWeb Browsers
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, mature codebase (ex: what can slow things down when you have old code talking to new code and what can we do about it?)
Use several programming languages (e.g., C++, JavaScript, Kotlin, Rust, Python) and techniques to fix performance issues, with an emphasis on C++
Help to educate engineers on other teams about writing more performant code through code reviews, giving talks, and/or writing documentation
Work with driven, committed team members to help bring the Open Web to millions of people
Qualification
Required
5+ years experience as a software engineer
A solid understanding and strong working experience in C++
Experience developing performance critical software
Proven experience taking an experimental and measured approach to solving problems (measurement, and using experiments to diagnose an issue or prove out a solution)
Strong debugging skills in analyzing performance bottlenecks
An interest and ability to work in a distributed team (which requires good asynchronous written communication skills as well as good verbal communication skills)
Preferred
Experience with multithreading and concurrency, disk I/O, GPU, etc
Familiarity with Android or Windows OS application programming, profiling and debugging
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 (regardless of whether you contribute)
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)
Company
Mozilla
Mozilla provides internet solutions and offers firefox, thunderbird, and raindrop.
501-1000 employees
H1B Sponsorship
Mozilla has a track record of offering H1B sponsorships. Please note that this does not
guarantee sponsorship for this specific role. Below presents additional info for your
reference. (Data Powered by US Department of Labor)
Distribution of Different Job Fields Receiving Sponsorship
Represents job field similar to this job
Trends of Total Sponsorships
2025 (2)
2024 (5)
2023 (4)
2022 (3)
2021 (2)
2020 (6)
Funding
Current Stage
Late StageTotal Funding
$2.3MKey Investors
AOL
2005-01-01Angel· $0.3M
2003-07-15Series Unknown· $2M
Leadership Team
John Shaughnessy
Manager, Engineering and Ecosystem Strategy
Recent News
2025-12-31
2025-12-24
2025-12-21
Company data provided by crunchbase