Senior Machine Learning Engineer, Applied AI Modeling

About this role

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, 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. 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 The Team & Role
The Firefox team is building the next generation of intelligent, privacy-aware experiences for the web. 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.


We’re looking for a
Senior Machine Learning Engineer
with a strong focus on
applied AI
and
modern LLM-based applications
. 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.


What You’ll Do

• 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.
• U...