Senior Staff Performance Engineer, Firefox - Mozilla

Why Mozilla?

Mozilla Corporation is the non-profit-backed technology company that has shaped the internet for the better over the last 25 years. We make pioneering brands like Firefox, the privacy-minded web browser. Now, with more than 225 million people around the world using our products each month, we’re shaping the next 25 years of technology and helping to reclaim an internet built for people, not companies. Our work focuses on diverse areas including AI, social media, security and more.

The Mozilla Corporation is wholly owned by the non-profit 501(c) Mozilla Foundation. This means we aren’t beholden to any shareholders — only to our mission. Along with thousands of volunteer contributors and collaborators all over the world, Mozillians design, build and distribute open-source software that enables people to enjoy the internet on their terms.

About this team and role

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.

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

What you'll bring

• BS/MS in CS, CE and 7+ years relevant experience
• A mastered understanding of programming in C++
• An understanding of programming in JavaScript
• Proven experience developing performance critical software
• 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 (good asynchronous written communication skills as well as good verbal communication skills)

Bonus points

• 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