Senior Staff Machine Learning Engineer, ML Understanding

Reddit is a community of communities It’s built on shared interests, passion, and trust, and is home to the most open and authentic conversations on the internet

Every day, Reddit users submit, vote, and comment on the topics they care most about With 100,000+ active communities and approximately 130 million daily active unique visitors, Reddit is one of the internet’s largest sources of information

For more information, visit www.redditinc.com .

We’re looking for a Senior Staff Machine Learning Engineer to lead Reddit’s next-generation user understanding initiative: building a unified, high-fidelity representation of each user that powers personalization across the platform.

This role requires deep expertise in mainstream ML user modeling approaches (e.g., large-scale embeddings, user interest modeling, affinities, behavioral signals) and the ability to reimagine these systems in the GenAI era—leveraging LLMs and foundation models to unlock step-change improvements in fidelity, adaptability, and expressiveness.

You will set the technical direction for this space, leading the design and implementation of Reddit’s core user representation layer—spanning embeddings, interest modeling, and key user attributes

You’ll ensure this foundation is scalable, reliable, and widely adopted across Feeds, Search, Notifications, and Ads, partnering closely with product, infrastructure, and downstream ML teams to drive measurable impact.

This is a high-impact role The systems you build will shape how hundreds of millions of people experience Reddit every day—what they see, what they discover, and the communities they connect with

Your work will directly advance personalization and relevance at global scale, strengthening Reddit as a platform for meaningful connection and belonging.

What youll do

• Design User Understanding Strategy: Define a unified user understanding framework and strategy: how users are represented (embeddings, tags, attributes, LLM-based user profile), how they are computed, stored, and exposed.
• Provide thought leadership in user understanding and user modeling by setting a long-term technical vision and advancing the state-of-the-art in the fie