Sr. Staff Software Engineer, Browser (New Products)

This position is listed on behalf of a partner company, which manages all applications and next steps. Our partner is looking for a Sr. Staff Software Engineer, Browser (New Products) based in Canada. As a senior individual contributor, you will help explore new possibilities in browser technology by combining deep systems engineering with rapid experimentation and technical innovation. You will investigate browser internals, develop engine-level prototypes, and evaluate new capabilities that improve performance, correctness, and programmatic interaction with web content. Working closely with a small, technically focused team, you will turn complex engineering questions into measurable results that inform product direction. This role offers the opportunity to tackle challenging problems across browser architecture, web platform behavior, and AI-enabled workflows. You will bring technical rigor, independent judgment, and a hands-on approach to building and validating new ideas. Your work will help shape how browser technology evolves to support emerging applications and more capable AI agents. Accountabilities - Design and implement experiments across browser engine subsystems, investigating how internal data structures and execution behavior influence performance, correctness, and the information available to developer tools. - Evaluate approaches for representing and exposing browser state efficiently and accurately, assessing trade-offs involving information loss, implementation complexity, and compatibility with dynamic web content. - Prototype browser engine capabilities that enable reliable programmatic interaction with websites, accounting for document structure, layout, navigation, and event handling.

- Instrument browser behavior and evaluate new implementations through repeatable tasks, measuring performance and correctness while isolating the impact of individual changes. - Document unsuccessful experiments as carefully as successful ones, validate findings across different workloads, and determine whether improvements generalize beyond the conditions used during development. - Profile the overhead introduced by new capabilities and optimize performance when supported by measurement and evidence. - Use AI-assisted coding and analysis tools to accelerate experimentation while validating their output through debugging, testing, and reproducible measurements. - Collaborate with the technical lead and other specialists to investigate unfamiliar systems, assess technical trade-offs, and inform the direction of new browser-based products. Requirements: - Extensive hands-on experience with at least one browser engine subsystem, such as the Document Object Model (DOM) and Web APIs, layout and rendering, accessibility, JavaScript runtimes, networking, or process architecture, including substantial implementation work and an understanding of related subsystems. - Strong proficiency in C++ or Rust , with experience navigating large systems codebases and practical knowledge of memory ownership, concurrency, object lifetimes, and performance debugging. - Ability to develop JavaScript and scripting tools to exercise browser behavior, automate tests, and collect reliable measurements. - Demonstrated ability to investigate unfamiliar code, formulate precise hypotheses, build effective prototypes, and interpret results while distinguishing implementation effects from variations in websites, workloads, or model behavior. - Strong understanding of web platform behavior and compatibility, including the relationships between document structure, script execution, rendering, navigation, and user interaction. - Experience with profiling, tracing, regression testing, or conformance testing, supported by a disciplined approach to reproducible evidence and performance evaluation.