Frontend Senior Software Engineer

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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 Performance Tools team builds frameworks and tools that help engineers measure and improve performance across Mozilla products. We’re a distributed team based in North America and Europe, supporting both internal Mozilla engineers and the broader web developer community through tools like the Firefox Profiler.

In this role, you will work on the user interface of the Firefox Profiler. This includes implementing interactive performance visualizations, handling large-scale performance data efficiently in the browser, and improving usability for engineers across Mozilla. You will collaborate with systems engineers, browser developers, and other teams working on performance.

What you’ll do: 

• Design and develop modern, interactive UI components for the Firefox Profiler using TypeScript, React, Redux, and related web technologies.
• Build high-performance, scalable, accessible, and maintainable user interfaces that visualize complex performance data.
• Engage with other Firefox engineers to help them learn how to use our tools efficiently, and develop projects to serve them better.
• Engage with the performance team efforts such as bug triage and strategy.
• Promote and encourage the use of our performance tools within and beyond Mozilla by writing and talking about them.
• Engage with our community and mentor volunteers contributing to the codebase.

• 5+ years of experience in JavaScript/TypeScript, React, Redux, and browser-based UI development.
• A strong background in building complex, interactive UIs that manage large data sets efficiently.
• Knowledge of profiling, performance tooling, and testing.
• Knowledge of frontend testing frameworks (e.g., Jest, React Testing Library) and best practices in maintainable UI codebases.
• Strong and respectful communication skills and ability to collaborate across engineering teams.
• Experience working with performance visualization is a plus.
• Familiarity with the Firefox Profiler or Chrome DevTools is a plus.
• Commitment to our values:
• • Welcoming differences
  • Being relationship-minded
  • Practicing responsible participation
  • Having grit

• 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)

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 [email protected] 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: R2934