Founding Research Engineer - RL Environments & Evals | San Francisco

Job Description

Job Description

Have you built the environments and benchmarks that AI models learn from? Then this is your seat.

A seed-stage AI company in San Francisco partners closely with the leading AI labs, creating the reinforcement learning tasks, environments and benchmarks those labs use to train and test their models. You'd be their first engineer in San Francisco, and from about month six you'd lead your own team.

What you'll own

• Designing and building RL tasks and environments that frontier models train on
• Eval harnesses and benchmarks that show whether a model actually got better
• Post-training experiments, and turning what you learn into better environments
• Hiring and leading a team in San Francisco as the company grows

Must-haves

• You've built RL environments, tasks, benchmarks or evaluation harnesses with your own hands. Only operating an existing eval pipeline won't be enough here.
• Hands-on post-training experience (SFT, DPO, GRPO, RLHF or similar), ideally with a result you can point to, such as a benchmark score that moved
• Able to work full time from the San Francisco office now, on a 9-9-6 schedule
• Roughly 1–5 years of experience

Bonus points

• A benchmark or post-training project of your own, public on GitHub
• Experience at a data or RL-environment company, or on a post-training team at an AI lab or strong university lab
• You're outside San Francisco but genuinely AI-obsessed and ready to move

What's in it for you

• $150k–$200k base, plus equity (0.25–0.5%)
• On top of that, 4% of project profits, which can realistically bring total pay to around $500k a year
• A founding role working side by side with frontier labs

Good to know

• Full-time, on-site in San Francisco, 9-9-6
• Sponsorship is limited: please tell us your exact work authorization up front
• Process: founder call → culture conversation with the co-founder → take-home build (RL and evals) → one day on site → offer

When you apply, please include

• Your CV (PDF) and your LinkedIn URL , plus GitHub if you have one
• The environment, harness or benchmark you built, what it tested, and who relied on it
• Your current location, and confirmation that full-time San Francisco on 9-9-6 works for you
• Your visa or citizenship status (for example US citizen, green card, H-1B, F-1/OPT including dates, O-1, TN), and if you'll need sponsorship, now or in the future
• Your base salary expectation, your earliest start date, and any other interview processes you're in

Does this sound like you? Apply now. If you're a match, we'll be in touch within 3 working days.

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