Senior Browser Engine Engineer – Prototyping & Performance

Mozilla; United States; On-site; USD 195,000 - 260,000; Full time

Benefits offered by this job

Generous performance-based bonus plans

Medical, dental, and vision coverage

Generous retirement contributions with

home office stipend

Annual professional development budget

Parental leave

Employee referral bonus program

Job summary

Mozilla is seeking experienced browser engineers to join a team exploring new applications of browser technology. You will design experiments in engine subsystems, implement changes, and verify improvements with rigorous measurements.

You will own engine-level investigations and prototypes, collaborating with a technical lead. You should bring deep browser-engine experience, strong C++ or Rust skills, and a track record of analyzing web platform behavior.

Qualifications

• Deep hands-on expertise in at least one browser engine subsystem.
• Strong proficiency in C++ or Rust and memory ownership.
• Ability to investigate unfamiliar code and construct prototypes.
• Strong understanding of web platform behavior and compatibility.
• Experience with profiling, tracing, regression tests, or conformance tests.

Responsibilities

• Design and implement experiments within browser engine subsystems.
• Evaluate ways to represent and expose browser state.
• Prototype engine capabilities for programmatic interaction with web content.
• Instrument browser behavior and compare changes against repeatable tasks.
• Profile overhead of new capabilities and validate with tests.

Skills

Browser engine expertise

C++ or Rust

Memory ownership

Concurrency

Object lifetimes

Performance debugging

JavaScript tooling

Investigate unfamiliar code

Prototype and prototype tooling

Web platform compatibility

Profiling and tests

AI agents curiosity

Job description

Mozilla is seeking experienced browser engineers to join a team exploring new applications of browser technology. You will design experiments in engine subsystems, implement changes, and verify improvements with rigorous measurements.

You will own engine-level investigations and prototypes, collaborating with a technical lead. You should bring deep browser-engine experience, strong C++ or Rust skills, and a track record of analyzing web platform behavior.