Remote opportunity at
MozillaSr. Staff Software Engineer, Browser (New Products)
Mozilla is recruiting a Sr. Staff Software Engineer for a compact group that explores new uses of browser technology, working remotely. The post is an individual-contributor…
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About This Role
Mozilla is recruiting a Sr. Staff Software Engineer for a compact group that explores new uses of browser technology, working remotely. The post is an individual-contributor role with genuine say over engine-level inquiries and code, operating alongside the group's lead engineer. The core work turns hard systems questions into experiments, implements engine changes, and determines which ideas actually help. Typical tasks include building trial implementations inside browser engine subsystems, analysing…
Job Description
Mozilla is recruiting a Sr. Staff Software Engineer for a compact group that explores new uses of browser technology, working remotely. The post is an individual-contributor role with genuine say over engine-level inquiries and code, operating alongside the group's lead engineer. The core work turns hard systems questions into experiments, implements engine changes, and determines which ideas actually help.
Typical tasks include building trial implementations inside browser engine subsystems, analysing how internal structures and execution paths influence speed, accuracy and developer tooling, and comparing ways to represent browser state without losing fidelity. The engineer prototypes reliable programmatic control of web content, examines how page structure, layout, moving between pages and input events interact, measures each change against repeatable workloads, and confirms results on workloads beyond the prototype's home turf. Overhead from new features is profiled, and both successful and failed trials get written up.
Candidates should have concentrated expertise in one engine subsystem, such as document APIs, rendering and layout, accessibility, scripting runtimes or the networking stack, along with the ability to follow an implementation's effects into neighbouring components. Strong C++ or Rust, comfort in a sprawling codebase, and comfort with memory ownership, parallel execution, object lifetimes and debugging slowdowns are necessary. The posting asks for precise hypotheses, separation of an implementation's effects from site and workload variation, and reproducible evidence for performance claims. Interest in AI agents and agent frameworks, and an understanding of how low-level choices shape what an agent sees, are also sought.
Extra credit goes to contributors on Gecko, Servo, Blink, WebKit or other engines; keeping an open-source project alive; leading a small group building something new; and experience in accessibility, browser security, profiling or evaluating agent workflows. US pay ranges run from $195,000 to $260,000 in Tier 1 locations, $179,000 to $239,000 in Tier 2 and $166,000 to $221,000 in Tier 3. Listed benefits include performance-based bonuses, medical, dental and vision coverage, retirement contributions that vest immediately, quarterly wellness days, country holidays with a birthday day off, a home-office stipend, a development budget, a well-being stipend and paid parental leave.
Responsibilities
- Design and implement trial changes within browser engine subsystems
- Look into how inner data layouts and runtime paths shape speed, correctness and developer tooling
- Prototype dependable programmatic control of web content
- Benchmark each change, isolate its effect and confirm gains beyond the prototype's test workloads
- Profile the overhead of new capabilities and pursue improvements the data supports
- Document failed and successful experiments alike, and use AI tools while checking their output
Requirements
- Concentrated expertise in one engine area, such as document APIs, rendering and layout, accessibility, scripting runtimes or the networking stack
- Strong C++ or Rust, plus experience in a large systems codebase
- Familiarity with how memory is owned, how threads interleave, how long objects live, and how to debug slowdowns
- Ability to form a precise hypothesis and build a useful prototype in unfamiliar code
- Understanding of web platform behaviour and compatibility
- Practice with profilers, trace tools and regression or conformance suites
- Interest in AI agents and agent harnesses
Qualifications
- Past work on Gecko, Servo, Blink or WebKit codebases, or any other engine
- Track record of looking after an open-source project
- Leading technically within a compact group that builds something new
- Experience in accessibility, browser security, profiling or evaluating agent workflows
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 role works alongside the group's lead engineer.
What are the US pay ranges?
They are $195,000 to $260,000 for Tier 1 locations, $179,000 to $239,000 for Tier 2 and $166,000 to $221,000 for Tier 3.
What technical depth is needed?
Real depth in one browser engine area, plus strong C++ or Rust, is needed.
What kind of team is it?
According to the posting, the group is small and looks at new uses for browser technology.
Which languages are named?
C++ or Rust are named as the core languages for the role.
Sample Interview Questions
AI-generated questions tailored to this specific role — a preview of the full practice set.