Senior Systems Software Engineer

Overview Join to apply for the Senior Systems Software Engineer role at 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. And we’re doing this while never losing our focus on our core mission – to make the internet better for people. 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 be responsible for low‑level programming of the Firefox Profiler and other tools. Your focus will be on delivering an effective toolset for Firefox developers looking to track down and seize every opportunity to improve the quality of experience for our users. You will work closely with performance experts to identify and surface the most valuable measurements across a variety of platforms. What You’ll Do Develop new features for the Firefox Profiler that will provide browser engineers and web developers with insight to improve the experience for their users. Expand the breadth of data captured by the Firefox Profiler without compromising on performance. Engage with the performance team efforts such as bug triage and strategy. Engage with other Firefox engineers to help them learn how to use our tools efficiently, and develop projects to serve them better. 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. What You’ll Bring 5+ years of experience in systems software engineering using C++. 1+ year of experience in Rust. Expertise in at least one of the following operating system APIs and familiarity with the others: Windows/Linux/macOS/Android. Experience working on and debugging large multi‑threaded applications and memory management. Strong and respectful communication skills and ability to collaborate across engineering teams. Familiarity with any of the following skills would be a plus: JavaScript, Java, Android development, Python. Commitment to our values: Welcoming differences, Being relationship‑minded, Practicing responsible participation, Having grit. 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). 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 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, religion, gender identity, color, national origin, pregnancy, ancestry, domestic partner status, disability, sexual orientation, age, genetic predisposition, medical condition, marital status, citizenship, 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. Referrals increase your chances of interviewing at Mozilla by 2x. Get notified about new Senior System Software Engineer jobs in Paris, Île‑de‑France, France. #J-18808-Ljbffr