24 hours ago
Base Salary
$138k - $217k/yr
Responsibilities
- Design and implement experiments within browser engine subsystems and investigate their effects on performance, correctness, and developer-tool interfaces.
- Evaluate efficient and accurate ways to represent and expose browser state, including tradeoffs involving information loss, complexity, and dynamic web compatibility.
- Prototype engine capabilities supporting reliable programmatic interaction with web content across document structure, layout, navigation, and event handling.
- Instrument browser behavior, measure performance and correctness against repeatable tasks, isolate changes, and document both successful and unsuccessful experiments.
- Profile overhead from new capabilities and pursue improvements supported by measurement.
- Use AI tools, agent harnesses, and coding tools to accelerate development while verifying results 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, with the ability to build JavaScript and scripting tools for measurement.
- Ability to investigate unfamiliar code, form precise hypotheses, construct useful prototypes, and interpret results amid workload and website variability.
- Strong understanding of web-platform behavior, compatibility, document structure, script execution, rendering, and user interaction.
- Experience with profiling, tracing, regression tests, or conformance tests and with grounding performance claims in 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 desirable.
- Experience maintaining an open-source project, providing technical leadership on a small product team, or working with accessibility infrastructure, browser security, profiling, or automated agent-workflow evaluation is desirable.
Benefits
- Performance-based bonus plans for eligible employees.
- Medical, dental, and vision coverage.
- Retirement contributions with immediate vesting.
- Quarterly company 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, employee referral bonus program, and other country-dependent benefits.
- Remote role, as indicated by the posting.
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.