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Research Engineer

Letta

Office

San Francisco Office

Full Time

Building the AI Operating System

We believe AI's future isn't just more intelligent language models, it's agents that remember, learn, and evolve over time. We're building the AI Operating System to turn stateless models into perpetual and self-improving intelligence.

Letta is founded by AI researchers from UC Berkeley's Sky Computing Lab (the same lab that produced Spark → Databricks and Ray → Anyscale), and the creators of MemGPT. We’re backed by leaders in AI and infra, including Jeff Dean (Chief Scientist at Google AI), Clem Delangue (CEO of HuggingFace), and Cris Velenzuela (CEO of Runway). Our technology is already being deployed in production to create autonomous, self-improving AI agents at companies like 11x and BILT Rewards.

We’re looking for incredibly talented individuals to join our team of AI researchers and engineers to create the first AI OS with human-like memory and learning capabilities. Join us and build the future of open AI, in the heart of San Francisco.

👾 Read more about Letta on TechCrunch, our blog, and on our GitHub (17k+ stars).

📃 Research whitepaper: Sleep-time Compute: Beyond Inference Scaling at Test-time

Note that this role is in-person (no hybrid), 5 days a week in downtown San Francisco.

LLMs are one piece of a complete agentic system. To build human-like AI that can reason, plan, learn, and remember, we need to engineer the new computer. We believe that the key research advancements that unlock these capabilities will happen from fast-paced open research at the application layer that mixes and matches the best models. 

At Letta, our research is focused on understanding the fundamental limitations of LLM-driven intelligence, and building the open model-agnostic application layer above LLMs.  As a research engineer, you will work closely with a world-class research team behind MemGPT (PhDs from UC Berkeley’s BAIR and Sky research labs) on agentic systems, memory, reasoning, and scaling test-time compute. You will productionize research developments in Letta’s OSS framework and cloud platform. 

Responsibilities: 

  • Developing Letta’s core agentic loops, which encompasses tool execution, stream parsing, reasoning, and more. 

  • Evaluating and improving performance of Letta’s agents framework with open models and new model types (e.g. reasoning models) 

  • Integrating LLM API providers into Letta’s framework 

Skills:

  • Extremely strong programming skills in Python 

  • Strong AI/ML fundamentals

  • Ability to stay up to date with new developments in agents/memory/LLM space

  • Experience in software engineering 

Examples of what you might work on: 

  • Adding memory management capabilities to voice agents 

  • Implementing constrained decoding to improve tool calling in open models 

  • Building systems for multi-agent coordination 

  • Benchmarking model performance

Signs it could be a great fit:

  • You want to be a part of turning a tiny startup into a trillion dollar company. You wonder what it would have been like to be at OpenAI when it was just a dozen people, or Google when it was just a couple grad students in a garage.

  • If you work / worked at a large tech company: you felt physically pained by the red tape and bureaucracy wedged between you and your potential impact.

  • You’re excited to go head-to-head with tech giants, frontier labs, and other startups that are many times our size in both headcount and funding.

  • You are against closed frontier AI that is controlled by a few private tech companies.

Signs it’s a bad fit:

  • You like having things planned out far ahead of time, and get stressed out when there’s nobody telling you exactly what to do. We look for people that thrive in ambiguity and can drive their own agenda.

  • You want to work a 9-5, and value clear separation of work from life. The stakes are high, and the only moat is execution and velocity. We work hard because incredible outcomes require incredible sacrifice – operating on a strict 9-5 guarantees failure.

  • You value titles or want to people-manage. Letta is a flat company where every researcher and engineer is an individual contributor.

  • You’re not interested in talking to customers, and prefer to stick to one part of the stack. At Letta everyone on the team engages directly with our customers and works across the stack.

Our Interview Process:

  • Initial screen (30 min)

  • Technical screen (1-1.5 hours)

  • Paid in-person work trial (2 days onsite in SF)

Research Engineer

Office

San Francisco Office

Full Time

August 3, 2025

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Letta

Letta.com

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