Mozilla

Senior Machine Learning Engineer, Applied AI Modeling

Remote US · Senior

Sponsorship not specified$163k-$218kDetected 27 days ago

Code ReviewMachine LearningNLPLLMsRAGA/B TestingCommunication

About the role

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, and Pocket, a service for keeping up with the best content online.
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.

Develop and fine-tune large language models (LLMs) for intelligent, safe, and responsive browser interactions.
Use modern ML tooling (e.g., Hugging Face, LangChain, Weights & Biases, Ray, or similar) to support end-to-end model development, including experimentation, evaluation, and rollout.
Collaborate closely with product and engineering partners to design, iterate, and launch features that align with user needs and Mozilla's values.
Design and implement experiments to test model behavior in production, analyze results, and iterate based on findings.
Document and share your work, participating in code reviews and team design discussions.
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.
You will help conceptualize, prototype, and deploy user-facing experiences grounded in Generative AI, working collaboratively with engineering, design, and product to bring these capabilities to life in Firefox.
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.
Join us to work on the Web as the platform and help create more opportunity and innovation for everyone online.

Strong understanding of prompt engineering, embedding-based retrieval, and evaluation strategies for generative applications.
Familiarity with on-device model optimization or privacy-preserving ML.
Experience working in a browser context or with web technologies.
4+ years of experience in applied machine learning, with a focus on natural language processing or generative AI.
Hands-on experience fine-tuning and evaluating LLMs using modern tools and open-source libraries.
Experience using ML tooling to lead the end-to-end lifecycle of model development-from data exploration to deployment-ready artifacts.
Track record of building user-facing AI features, especially where privacy, latency, and usability are critical.
Clear communication skills and ability to collaborate with multi-functional partners on a distributed team.
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
One-time home office stipend
Quarterly well-being stipend
Considerable paid parental leave
Employee referral bonus program
Other benefits (life/AD&D, disability, EAP, etc. - varies by country)
Commitment to diversity, equity, inclusion, and belonging

Contributions to open-source ML frameworks or model hubs.
This means we aren't beholden to any shareholders - only to our mission.
As part of this evolution, we are embedding modern AI and LLM-driven features directly into the browser-empowering users while safeguarding their autonomy and data.
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.

omestic 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

This listing is sourced directly from Mozilla's careers page and normalized into a canonical job model.