Senior Software Engineer - Firefox Performance

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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. And we’re doing this while never losing our focus on our core mission – to make the internet better for people. 

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.

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 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, mature codebase (ex: what can slow things down when you have old code talking to new code and what can we do about it?)

• Use several programming languages (e.g., C++, JavaScript, Kotlin, Rust, Python) and techniques to fix performance issues, with an emphasis on C++

• Help to educate engineers on other teams about writing more performant code through code reviews, giving talks, and/or writing documentation

• Work with driven, committed team members to help bring the Open Web to millions of people 

What you’ll bring: 

• 5+ years experience as a software engineer

• A solid understanding and strong working experience in C++

• Experience developing performance critical software

• Proven experience taking an experimental and measured approach to solving problems (measurement, and using experiments to diagnose an issue or prove out a solution)

• Strong debugging skills in analyzing performance bottlenecks

• An interest and ability to work in a distributed team (which requires good asynchronous written communication skills as well as good verbal communication skills)

• Commitment to our values:

  • Welcoming differences

  • Being relationship-minded

  • Practicing responsible participation

  • Having grit

Bonus Points: 

• Experience with multithreading and concurrency, disk I/O, GPU, etc

• Familiarity with Android or Windows OS application programming, profiling and debugging

What you’ll get:

• Generous performance-based bonus plans to all eligible employees - we share in our success as one team

• Rich medical, dental, and vision coverage

• Generous retirement contributions with 100% immediate vesting (regardless of whether you contribute)

• Quarterly all-company wellness days where everyone takes a pause together

• Country specific holidays plus a day off for your birthday

• One-time home office stipend

• Annual professional development budget

• Quarterly well-being stipend

• Considerable paid parental leave

• Employee referral bonus program

• Other benefits (life/AD&D, disability, EAP, etc. - varies by country)

About Mozilla 

Mozilla exists to build the Internet as a public resource accessible to all because we believe that open and free is better than closed and controlled. When you work at Mozilla, you give yourself a chance to make a difference in the lives of Web users everywhere. And you give us a chance to make a difference in your life every single day. Join us to work on the Web as the platform and help create more opportunity and innovation for everyone online.

Commitment to diversity, equity, inclusion, and belonging

Mozilla understands that valuing diverse creative practices and forms of knowledge are crucial to and enrich the company’s core mission.  We encourage applications from everyone, including members of all equity-seeking communities, such as (but certainly not limited to) women, racialized and Indigenous persons, persons with disabilities, persons of all sexual orientations, gender identities, and expressions.

We will ensure that qualified individuals with disabilities are provided reasonable accommodations to participate in the job application or interview process, to perform essential job functions, and to receive other benefits and privileges of employment, as appropriate. Please contact us at hiringaccommodation@mozilla.com to request accommodation.

We are an equal opportunity employer. We do not discriminate on the basis of race (including hairstyle and texture), religion (including religious grooming and dress practices), gender, gender identity, gender expression, color, national origin, pregnancy, ancestry, domestic partner status, disability, sexual orientation, age, genetic predisposition, medical condition, marital status, citizenship status, military or veteran status, or any other basis covered by applicable laws.  Mozilla will not tolerate discrimination or harassment based on any of these characteristics or any other unlawful behavior, conduct, or purpose.

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Req ID: R2936