Senior Research Engineer, Post-Training

Senior Research Engineer, Post-Training

About CHAI AI

CHAI is a social AI platform where millions of people create, share, and talk to AI characters. As of Sep 2026, it has 10 million active users and $100 million ARR. After receiving over $55M in funding from investors such as AMD and CoreWeave, CHAI AI is actively hiring engineers to expand its team.

About the team

Engineering is 15–20 people with a flat structure. High impact on the product, fast iteration, and clear metrics to measure against.

What you will work on

Own the pipeline that turns raw roleplay data into better model behavior — SFT, RL, reranking, data curation, whatever it takes. You'll run the loop from eval signal to next training run and decide what to try next.

You might thrive in this role if you…

(minimum/Preferred requirements)

• 2+ years of software engineering experience
• High motivation and talented.
• High ownership: comfortable with ambiguity, able to define the problem and the plan rather than execute a predefined spec.
• Able to work in person at our Palo Alto Office.

Compensation and benefits

Top pay AI startup in Bay Area. $609,000 – $900,000, paid 100% in cash.

We benchmark against total comp at Meta, Google, and OpenAI — and pay that number in cash, not equity, with the option to trade a portion of cash for stock options.

Health, 401k, unlimited PTO.

Our interview process

We run a fast process - an offer can be given within 7 days of first contact.

1. 20 minute phone screen with our founder or engineer
2. 20 minute personality assessment
3. Take home assessment. 60-90 minutes to complete.
4. One day onsite interview.