Staff Data Scientist, Firefox

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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 groundbreaking brands like Firefox, the privacy-minded web browser. Now, with more than 200 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, privacy, 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 Firefox Data Science team partners with Product and Engineering to grow usage of our flagship product: Firefox , the privacy-minded web browser. Our work informs prioritization, investment decisions, and the long-term growth strategy across Firefox.

This Staff Data Scientist will own the analytical strategy for a major product area: identifying the right questions, defining how success is measured, and driving decisions that shape Firefox’s growth trajectory. You will be a strategic partner to product and engineering leadership: framing problems, designing measurement approaches, and translating data into clear recommendations that influence roadmap and resource allocation. You will also raise the analytical bar across the team by establishing frameworks, mentoring other data scientists, and setting standards for how we measure and learn. This role requires the judgment to know which problems matter most, the technical depth to solve them rigorously, and the influence to ensure the work drives action.

What you’ll do:

• Own the analytical strategy for a product area: identifying the highest-leverage questions, defining the measurement framework, and ensuring data-driven decisions
• Serve as a strategic partner to product and engineering leadership, translating ambiguous business problems into analytical approaches and clear, actionable recommendations
• Define north-star metrics and measurement strategies to set goals, evaluate progress, and make trade-offs
• Design and oversee experiments and causal analyses, ensuring methodological rigor and that results drive real product decisions
• Develop and maintain a deep understanding of user growth dynamics: how acquisition, activation, and retention interact to drive growth, and use that understanding to diagnose metric movements, explain trends to leadership, and anticipate emerging risks or opportunities
• Contribute and own areas of the team’s forecasting and growth modeling efforts, helping translate statistical models into actionable growth strategies
• Mentor and elevate other data scientists through code review, methodology guidance, and establishing reusable analytical frameworks
• Represent data science in cross-functional forums, making the case for what the data shows even when it challenges prevailing assumptions
• Drive alignment across data science, data engineering, and product on shared priorities like data quality, metric definitions, and instrumentation

What you’ll bring:

• 8+ years of experience in data science, analytics, or applied quantitative analysis, with a track record of shaping product strategy through data
• Demonstrated ability to lead complex, cross-functional analytical initiatives from problem framing through stakeholder alignment to decision
• Deep expertise in experimentation (A/B testing) and causal inference, with strong judgment about when each method applies and what conclusions they support
• Advanced proficiency in SQL and Python for analysis, modeling, and validation
• Experience defining and owning product metrics that teams actually use to make decisions
• Strong opinions, loosely held: you can take a position on what the data says, advocate for it clearly, and update when the evidence changes
• Track record of mentoring or technically leading other data scientists
• 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)

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 orientation s, 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 View email address on us.fitly.work 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

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Req ID: R3103