Software Engineer, RL Data

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Job details

  • ONSITE
  • FULL_TIME
  • San Francisco
  • United States
  • Verified 2026-09-25
  • Source: Cursor public Ashby board

Original job description

Our mission is to automate coding. The first step in our journey is to build the best tool for professional programmers, using a combination of inventive research, design, and engineering. Our organization is very flat, and our team is small and talent dense. We particularly like people who are truth-seeking, passionate, and creative. We enjoy spirited debate, crazy ideas, and shipping code.

Software Engineer, Reinforcement learning  

  • SpaceXAI is building the future of coding. We train frontier coding agents and scale RL on real user data to make them increasingly effective.

 

About the role

 

  • As a Software Engineer on the RL Data team at SpaceXAI, you'll create the tasks, rewards, and environments that train our coding agents. The team owns the data that goes into training: what the model is asked to do, how we score it, and the setups it learns in.

   

What you’ll do

 

  • Designing a task set that teaches a specific agent capability, then iterating on it from traces and evals until the model actually gets better.

  • Reading a pile of agent traces, finding a failure mode or a surprising behavior, and building a system that surfaces more of the same.

  • Turning a one-off recipe into something other teams can reuse: better rewards, cleaner environments, tighter data quality.

  • Partnering with research on whether a dataset is actually teaching the thing we think it is.

       

You may be a fit if

  • You write careful, fast code and have strong software engineering fundamentals.

  • You like setting tasks: breaking a fuzzy capability into something concrete you can measure.

  • You have an infra, data, or distributed systems background. RL experience is a plus, not a requirement.

  • You enjoy looking at messy real-world agent behavior and turning it into a dataset or a tool.

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