Sr. Staff Software Engineer, Browser (New Products)

Mozilla's New Products group is a small team building new things on top of browser engine technology. We're hiring a hands-on, senior IC to run experiments inside browser engine internals and find out which ideas actually hold up. What you'd do: design and build experiments in engine subsystems (DOM, layout, accessibility, JS runtime, networking), prototype features that let programs interact with web pages reliably, and measure everything. That means repeatable benchmarks, profiling overhead, and writing up the experiments that didn't work too. You'll use AI tools heavily, but you'll verify what they produce by testing and measuring it. You likely have: deep experience in at least one browser subsystem, strong C++ or Rust, comfort in a very large codebase, a solid grasp of how the web platform behaves, and a real interest in AI agents and their tooling. Contributions to Gecko, Servo, Blink or WebKit are a big plus. US: https://job-boards.greenhouse.io/mozilla/jobs/8265116 (https://job-boards.greenhouse.io/mozilla/jobs/8265116) Canada: https://job-boards.greenhouse.io/mozilla/jobs/8265117 (https://job-boards.greenhouse.io/mozilla/jobs/8265117)