Staff Firefox Performance Engineer

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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 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 bottlenecksLearn about a wide variety of problems and solutions across a large, complex, and evolving codebaseUse several programming languages (e.g., C++, JavaScript, Kotlin, Rust, Python) and techniques to fix performance issues, with an emphasis on C++ and JavaScriptHelp to educate engineers on other teams about writing more performant code through code reviews, giving talks, implementing tooling, and/or writing documentationBreak down complex performance problems into actionable next steps and drive them to completionPartner with engineering teams across the organization to support performance efforts, and lead them within your areaContribute to the direction of performance benchmarks and help prioritize the improvements that matter mostOwn the performance of a significant area of the browser end to end, and contribute to the Performance team's technical roadmapWork with driven, committed team members to help bring the Open Web to millions of people What you'll bring: BS/MS in CS or CE, and 5+ years of relevant experienceDeep proficiency in C++Working proficiency in JavaScriptYou have proven experience developing performance-critical softwareYou 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 at least one of: multithreading and concurrency, disk I/O, or GPU workTrack record of driving projects to completion, including work spanning more than one engineer.Experience collaborating with engineers on other teams to deliver 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 patternsFamiliarity with Android or Windows OS application programmingA solid understanding of statisticsPrior experience working on a modern web browser We value a variety of voices on the Performance Team and at Mozilla. You don't need to check every box on this list to apply. What You’ll Get Generous performance-based bonus plans to all eligible employees - we share in our success as one teamRich medical, dental, and vision coverageGenerous retirement contributions with 100% immediate vesting (regardless of whether you contribute)Quarterly all-company wellness days where everyone takes a pause togetherCountry specific holidays plus a day off for your birthdayOne-time home office stipendAnnual professional development budgetQuarterly well-being stipendConsiderable paid parental leaveEmployee referral bonus programOther 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. Group: C Req ID: R3245 Hiring Ranges US Tier 1 Locations $163,000—$218,000 USD US Tier 2 Locations $150,000—$200,000 USD US Tier 3 Locations $139,000—$185,000 USD Remote US Applicant Privacy Notice Why Mozilla? At Mozilla, we’re serving humanity—by maintaining a safe, open internet—while also helping the individual humans employed here to reach their personal and professional goals. With a relatively small team serving hundreds of millions of people, a culture of exploration, and a commitment to mentorship, opportunities abound to learn and grow at Mozilla. Our values drive our actions Purpose is built into our work, with our mission driving every decisionWe challenge assumptions, the status quo, ourselves, and each otherWe are transparent: in our code, our business partnerships, and our everyday interactionsWe seek out people from diverse backgrounds and with perspectives different from our ownWe pair purpose with performance and put people ahead of profit Our impact is global 1000+ paid staff from over 30 countriesThousands of volunteer contributors across six continents2 global offices: Berlin and Toronto9 coworking space locations: San Francisco, San Mateo, London, Paris, Portland, Tulsa, Vancouver, Chicago, and BellevueHundreds of home offices globally Our benefits are world-class Flexible work environment (majority of Mozillians work remotely)Industry-leading paid parental leave (up to 26 weeks of fully paid leave for childbearing parents and up to 12 weeks for non-childbearing parents)Reimbursement for professional development (up to $3,000/year)A work setup including the latest hardware and software of your choice Company LeadershipPress CenterCareersMerch StoreContact Support Product HelpFile a BugLocalize MozillaSecurity Developers Developer EditionEnterpriseToolsMDNFirefox Release Notes Follow @Mozilla Bluesky (@mozilla.org)Instagram (@mozilla)LinkedIn (@mozilla)TikTok (@mozilla)Spotify (@mozilla) Follow @Firefox Bluesky (@firefox.com)Instagram (@firefox)YouTube (@firefoxchannel)TikTok (@firefox) Donate All languages Language English (Canadian) English (British) English Donate to the not-for-profit Mozilla Foundation. 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