Sr. Staff Software Engineer, Browser (New Products)
New
M
MozillaBrowser software
Location: Remote USFull-TimeStaff
SalaryUS Tier 1 Locations $195,000 — $260,000 USD; US Tier 2 Locations $179,000 — $239,000 USD; US Tier 3 Locations $166,000 — $221,000 USD
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Job Details
- Required Skills
- JavascriptC++Regression testingRust
Requirements
- Bring 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.
- Have implemented substantial changes to a browser engine and be able to trace their effects into neighboring subsystems.
- Demonstrate strong proficiency in C++ or Rust and experience navigating a large systems codebase.
- Have practical knowledge of memory ownership, concurrency, object lifetimes, and performance debugging.
- Be able to build JavaScript and scripting tools to exercise and measure work.
- Demonstrate the ability to investigate unfamiliar code, form a precise hypothesis, construct a useful prototype, and interpret results.
- Be able to separate implementation effects from variability in websites, workloads, or model behavior.
- Have a strong understanding of web-platform behavior and compatibility, including document structure, script execution, rendering, and user interaction.
- Have experience with profiling, tracing, regression tests, or conformance tests, and ground performance claims in reproducible evidence.
- Be curious about AI agents and willing to work directly with agent harnesses and coding tools.
- Nice to have contributions to Gecko, Servo, Blink, WebKit, or another browser engine.
- Nice to have experience maintaining an open-source project, technical leadership on a small team building a new product, or experience with accessibility infrastructure, browser security, profiling, or automated evaluation of agent workflows.
Responsibilities
- Design and implement experiments within browser-engine subsystems.
- Investigate how internal data structures and execution behavior affect performance, correctness, and developer-tools interfaces.
- Evaluate approaches for representing and exposing browser state efficiently and accurately, including their tradeoffs.
- Prototype engine capabilities that support reliable programmatic interaction with web content.
- Investigate how document structure, layout, navigation, and event handling affect correctness and performance.
- Instrument browser behavior and evaluate changes against repeatable tasks.
- Measure performance and correctness, isolate the effects of changes, and document successful and unsuccessful experiments.
- Check whether performance gains hold beyond the workloads used to develop a prototype.
- Profile overhead from new capabilities and pursue improvements when measurements justify them.
- Use AI tools to accelerate coding and analysis, verifying their output through debugging, tests, and measurement.
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