Mozilla Corporation is looking for a Senior Machine Learning Engineer with a strong focus on applied AI and modern LLM-based applications. The engineer 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.

Company: Mozilla Corporation

Role: Senior Machine Learning Engineer, Applied AI Modeling

Location: Remote US

Experience:

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

Role Focus: • Develop and fine-tune large language models (LLMs) for intelligent, safe, and responsive browser interactions • Apply retrieval-augmented generation (RAG), summarization, classification, and intent modeling techniques in real-world browser workflows • 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

Nice to have:

Familiarity with on-device model optimization or privacy-preserving ML
Experience working in a browser context or with web technologies
Contributions to open-source ML frameworks or model hubs

More skills:

Large language models (LLMs), Retrieval-augmented generation (RAG), Weights & Biases, Ray

Other:

Generous performance-based bonus plans
Rich medical, dental, and vision coverage
Generous retirement contributions with 100% immediate vesting
Quarterly all-company wellness days
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)

Senior Machine Learning Engineer, Applied AI Modeling

Skills Required

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More skills:

Other:

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