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Agent guide: [/agents.md](https://www.wearedevelopers.com/agents.md). --- # Staff Performance Engineer - **Company:** Mozilla Corporation - **Location:** United States (Remote available) - **Experience:** Expert - **Contract:** Permanent contract - **Skills:** Java (Programming Language), JavaScript (Programming Language), Microsoft Windows, Android Software Development, Apple Mac Systems, C++ (Programming Language), Profiling, Code Review, Computer Programming, Software Debugging, Linux, Firefox, Python (Programming Language), Web Standards, Rust (Programming Language), Multithreading, Concurrency, Kotlin, Production Code, Programming Languages - **Published:** September 23, 2026 - **Apply:** https://job-boards.greenhouse.io/mozilla/jobs/8121970 ## About the Role * BS/MS in CS, CE and 7+ years relevant experience * A mastered understanding of programming in C++ * An understanding of programming in JavaScript * You have proven experience developing performance critical software * You take an experimental and measured approach to solving problems (measurement, and using experiments to diagnose an issue or prove out a solution) * Proven skill in debugging and analyzing performance bottlenecks, and using profiling tools to diagnose and fix issues (VTune, Xperf, other sampling based profilers) * Experience with multithreading and concurrency, disk I/O, GPU * Proven track record of setting team goals and driving them to completion. * Experience motivating and aligning cross-functional teams to deliver on shared goals. * An interest and ability to work in a distributed team (which requires good asynchronous written communication skills as well as good verbal communication skills) Bonus points if you have any of the following: * Familiarity with Web Standards or patterns * Familiarity with Android or Windows OS application programming * A solid understanding of statistics * Prior experience working on a modern web browser ## Description The Mozilla Firefox Performance team is a community of engineers who care deeply about delivering the fastest browser possible. We are the team responsible for making all parts of the browser go fast. Our team is geographically-distributed, and working in the open is the norm. We contribute to the code driving the Firefox browser on a number of platforms - Windows, Android, Linux, and macOS. Our focus is on finding and fixing things that slow down the browser as well as helping other teams write fast and reliable code to make Firefox excellent for users. Do you value curiosity and enjoy finding a needle in a haystack? Do you approach problems by looking at the system as a whole? Do you want to help lead and shape the future of the Internet? Do you like making things blazingly fast? If so, we'd love to hear from you. What you'll do: * Write code and tests, build prototypes, tackle problems, profile and analyze performance bottlenecks * Learn about a wide variety of problems and solutions across a large, complex, and evolving codebase * Use several programming languages (e.g., C++, JavaScript, Kotlin, Rust, Python) and techniques to fix performance issues, with an emphasis on C++ and JavaScript * Help to educate engineers on other teams about writing more performant code through code reviews, giving talks, implementing tooling, and/or writing documentation * Independently define and drive actionable next steps from high level objectives * Work with engineering teams across the organization to assist and lead performance efforts * Shape the future of performance benchmarks, and set the proper priorities for the necessary improvements * Develop strategies for the future of the Performance team and the Organization as a whole * Work with driven, committed team members to help bring the Open Web to millions of people ## Related Videos - [Catching up on the basics you don't really need that much code](https://www.wearedevelopers.com/videos/903-catching-up-on-the-basics-you-don-t-really-need-that-much-code) - [Docker network without Docker](https://www.wearedevelopers.com/videos/1418-docker-network-without-docker) - [Kotlin Multiplatform - True power of native code reuse](https://www.wearedevelopers.com/videos/4-kotlin-multiplatform-true-power-of-native-code-reuse) - [WeAreDevelopers LIVE – AI and Privacy, On-Device AI and More](https://www.wearedevelopers.com/videos/1779-wearedevelopers-live-ai-and-privacy-on-device-ai-and-more) - [WeAreDevelopers LIVE - CSS or BS?](https://www.wearedevelopers.com/videos/1850-wearedevelopers-live-css-or-bs) - [Why Kotlin is the better Java and how you can start using it](https://www.wearedevelopers.com/videos/661-why-kotlin-is-the-better-java-and-how-you-can-start-using-it) ## Related Articles - [How We Built a Worry-Free System That Runs for 10+ Years – And What We’d Do Again](https://www.wearedevelopers.com/magazine/751-how-we-built-a-worry-free-system-that-runs-for-10-years-and-what-we-d-do-again) - [Dev Digest 106 - DHH in HD](https://www.wearedevelopers.com/magazine/394-dev-digest-106-dhh-in-hd) - [Dev Digest 120 - Apple and peers](https://www.wearedevelopers.com/magazine/455-dev-digest-120-apple-and-peers) - [The 8 Best Code Testing Tools](https://www.wearedevelopers.com/magazine/402-the-8-best-code-testing-tools) - [Dev Digest 129 - Now that's what I call private data!](https://www.wearedevelopers.com/magazine/468-dev-digest-129-now-that-s-what-i-call-private-data) - [Dev Digest 119 - ❤️ === ❤️](https://www.wearedevelopers.com/magazine/454-dev-digest-119)