Research Engineer / Scientist, Post-Training

Proficiency in python and deep learning frameworks eg. PyTorch

Expertise in post-training techniques e.g. SFT fine-tuning, reinforcement learning, reward models, preference learning

Ability to balance execution speed with empirical rigor

Proven track record of impactful research (breakthrough publications and/or open-source contributions)

Real-world impact beyond pure academic work

You want to maximize your impact: you want work on a small, incredibly talented team where every individual plays a huge role in the team's success. 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 of grad students in a garage.

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 fundamentally opposed to closed frontier AI that is controlled by a handful of billionaires and private tech companies.

You like stability, and get stressed out when there’s nobody telling you exactly what to do. We look for people that thrive in ambiguity and can intuit the most important problems by talking to customers and dogfooding our product.

You want to work a 9-5, and value clear separation of work from life. The stakes are the highest they've ever been, and the only moat is execution velocity. 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.

Initial screen (30 min)

Technical screen (1-1.5 hours)

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