Remote opportunity at
MozillaStaff Firefox Performance Engineer
Mozilla, the non-profit-backed company behind Firefox, is hiring a Staff Firefox Performance Engineer to work remotely. The Firefox Performance group spans several countries, works publicly by…
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About This Role
Mozilla, the non-profit-backed company behind Firefox, is hiring a Staff Firefox Performance Engineer to work remotely. The Firefox Performance group spans several countries, works publicly by default, and hunts down whatever makes the browser sluggish, while helping other groups write quicker and sturdier code. Its engineers work on Windows, Android, Linux and macOS. Because of the foundation structure behind the company, it answers to its mission rather than to investors.…
Job Description
Mozilla, the non-profit-backed company behind Firefox, is hiring a Staff Firefox Performance Engineer to work remotely. The Firefox Performance group spans several countries, works publicly by default, and hunts down whatever makes the browser sluggish, while helping other groups write quicker and sturdier code. Its engineers work on Windows, Android, Linux and macOS. Because of the foundation structure behind the company, it answers to its mission rather than to investors.
Typical work involves coding and testing, prototyping fixes, and profiling slowdowns in a large, changing codebase. C++ is the central language, with JavaScript also important, and Kotlin, Rust and Python may come up. The engineer educates colleagues elsewhere through reviews, presentations, tooling and documentation, and splits hard performance puzzles into actionable pieces and sees each one through.
The role also involves taking ownership of a major browser component's speed from investigation through delivery, influencing benchmark priorities and the team's roadmap, and collaborating across the organisation. Applicants need a bachelor's or master's in computer science or computer engineering and at least five years of relevant experience. Strong C++ and working JavaScript are required, along with a history of building performance-sensitive software and a measured, experimental mindset backed by profilers such as VTune, Xperf or sampling tools.
Practical depth in one or more areas such as threads, parallelism, storage I/O or graphics processing is needed, as is a record of carrying projects that involve several engineers and of working with colleagues in other groups. Clear written and spoken communication is important, since the team is spread across locations. Extra credit for web standards, Android or Windows development, statistics, or prior browser work. US hiring ranges are $163,000 to $218,000 in Tier 1 locations, $150,000 to $200,000 in Tier 2 and $139,000 to $185,000 in Tier 3.
Responsibilities
- Produce code and tests, prototype fixes, and profile slowdowns across the browser
- Turn knotty performance issues into workable actions and carry them through
- Help engineers on other teams write faster code through reviews, talks, tooling and documentation
- Work with engineers in other groups throughout the company on speed initiatives
- Influence benchmark design and rank which speedups count most
- Own the speed of a major browser area from investigation to delivery
Requirements
- Bachelor's or master's in CS or CE, plus five-plus years in the field
- Advanced C++ skills
- Functional command of JavaScript
- Proven experience with performance-critical software
- Experimental, measured approach to diagnosing issues and proving solutions
- Skill with profiling tools such as VTune, Xperf or sampling profilers
- Practical depth in one or more areas such as threads, parallelism, storage I/O or graphics processing
- Track record of delivering projects that involve more than one engineer
- Strong asynchronous written and verbal communication for a distributed team
Qualifications
- Knowledge of web standards and common web patterns
- Android or Windows application programming
- Solid understanding of statistics
- Earlier work on a contemporary browser codebase
Core Skills
Benefits
- Performance-based bonus plans
- Medical, dental and vision coverage
- Retirement contributions with immediate vesting
- Quarterly all-company wellness days
- Country-specific holidays and a birthday day off
- Home-office allowance, paid once
- Yearly budget for professional growth
- Quarterly stipend for wellbeing
- Paid parental leave
- Bonus for referring new hires
Frequently Asked Questions
Answers are based only on the employer’s listing; where it doesn’t say, neither do we.
Is the role remote?
Yes. The listing is remote and the team is geographically distributed.
What are the US pay ranges?
They are $163,000 to $218,000 for Tier 1 locations, $150,000 to $200,000 for Tier 2 and $139,000 to $185,000 for Tier 3.
What experience is required?
A BS or MS in computer science or computer engineering and at least five years of relevant experience are required.
Which languages matter most?
Deep C++ and working JavaScript are required. Kotlin, Rust and Python may also come up.
What benefits are listed?
Performance-based bonuses, medical, dental and vision coverage, retirement contributions with immediate vesting, and paid parental leave are among the listed benefits.
Sample Interview Questions
AI-generated questions tailored to this specific role — a preview of the full practice set.