5 hours ago
Base Salary
$166k - $260k/yr
Responsibilities
- Design and implement experiments within browser engine subsystems and investigate their effects on performance, correctness, and developer-tool interfaces.
- Evaluate approaches for representing and exposing browser state while analyzing information loss, complexity, and compatibility tradeoffs.
- Prototype engine capabilities for reliable programmatic interaction with web content, including document structure, layout, navigation, and event handling.
- Instrument, profile, and measure browser behavior using repeatable tasks, regression tests, tracing, and performance analysis.
- Document successful and unsuccessful experiments, validate results beyond development workloads, and pursue justified performance improvements.
- Use AI tools, agent harnesses, and coding tools to accelerate development while verifying outputs through debugging, testing, and measurement.
Requirements
- Deep hands-on expertise in at least one browser engine subsystem, such as DOM and Web APIs, layout and rendering, accessibility, JavaScript runtimes, or networking and process architecture.
- Strong proficiency in C++ or Rust and experience navigating a large systems codebase.
- Practical knowledge of memory ownership, concurrency, object lifetimes, and performance debugging.
- Ability to build JavaScript and scripting tools to exercise and measure browser-engine work.
- Demonstrated ability to investigate unfamiliar code, form precise hypotheses, build prototypes, and interpret experimental results.
- Strong understanding of web platform behavior, compatibility, document structure, script execution, rendering, and user interaction.
- Experience with profiling, tracing, regression tests, or conformance tests, with an emphasis on reproducible evidence.
- Curiosity about AI agents and willingness to work directly with agent harnesses and coding tools.
- Contributions to Gecko, Servo, Blink, WebKit, or another browser engine are preferred.
- Experience maintaining an open-source project, technical leadership in a small new-product team, or experience with accessibility infrastructure, browser security, profiling, or automated agent-workflow evaluation is preferred.
Benefits
- Performance-based bonus plans for eligible employees.
- Medical, dental, and vision coverage.
- Retirement contributions with immediate vesting.
- Quarterly company-wide wellness days, country-specific holidays, and a birthday day off.
- One-time home office stipend and annual professional development budget.
- Quarterly well-being stipend, paid parental leave, and employee referral bonus program.
- Additional benefits such as life and AD&D insurance, disability coverage, and EAP, varying by country.
- Remote work designation is indicated by the posting's #LI-REMOTE tag.
Tech Stack
Categories
About Mozilla
Mozilla builds open-source internet software, best known for the Firefox web browser, plus privacy tools like a VPN, password manager, and identity services. Its products are largely free and monetized through search partnerships and paid subscriptions, serving consumers, developers, and enterprises building for the web. Founded in 2005 and headquartered in San Francisco, Mozilla Corporation is wholly owned by the non-profit Mozilla Foundation.