Senior Browser Engine Engineer - Experiments & Performance

Mozilla; United States; Remote; USD 105,000 - 154,000; Full time

Benefits offered by this job

Generous performance-based bonus

Medical, dental, and vision coverage

Retirement contributions with vesting

Wellness days

Birthday holiday

Home office stipend

Professional development budget

Parental leave

Employee referral bonus

Job summary

Mozilla is seeking experienced browser engineers for a small team exploring new browser technologies. You will conduct engine-level experiments, implement changes, and work closely with a technical lead to drive engineering decisions.

The role emphasizes hands-on work on browser internals and performance optimizations. You should bring deep engine experience, proficiency in C++ or Rust, and a demonstrated ability to translate complex problems into prototypes.

Qualifications

• Deep hands-on expertise in at least one browser engine subsystem such as DOM/Web APIs, layout, or JS runtimes.
• Strong proficiency in C++ or Rust and memory ownership concepts.
• Experience profiling, tracing, and debugging with concrete results.

Responsibilities

• Design and implement experiments within browser engine subsystems.
• Investigate internal data structures and execution behavior for performance improvements.
• Prototype engine capabilities for reliable programmatic interaction with web content.
• Instrument browser behavior and compare changes with repeatable tasks.
• Profile overhead of new capabilities and verify results with tests and measurements.

Skills

Browser engine

C++/Rust

Memory & concurrency

Profiling & debugging

AI tools

Investigative mindset

Tools

JavaScript tooling

Job description

Mozilla is seeking experienced browser engineers for a small team exploring new browser technologies. You will conduct engine-level experiments, implement changes, and work closely with a technical lead to drive engineering decisions.

The role emphasizes hands-on work on browser internals and performance optimizations. You should bring deep engine experience, proficiency in C++ or Rust, and a demonstrated ability to translate complex problems into prototypes.