MatrAIx Fellow, RL Environments

About the fellowship

MatrAIx Fellows work on focused applied research projects that directly contribute to our core products and technology, with hands-on collaboration and mentorship from our team. The program suits PhD students who want to apply their research to real-world agent systems, and industry engineers or researchers who want to work on cutting-edge RL research and development.

In this track, you'll study how to build environments and rewards for training AI agents: how to make tasks realistic, how to verify success reliably, and how environment design shapes what agents learn.

What you'll do

• Scope your project with your MatrAIx mentor
• Build interactive, containerized environments with automated verifiers
• Run experiments on reward design, verifier robustness or reward hacking
• Present progress in regular research reviews with the team
• Deliver research outcomes that directly contribute to MatrAIx's products and technology

Who we're looking for

• A current PhD student, or a researcher or engineer in industry, with a background in CS, ML or a related field
• Strong foundation in RL: MDPs, policy optimization, reward design
• Fluent in Python; experience with PyTorch or JAX
• Hands-on experience with an RL or agent-systems project, in research or production
• Able to commit 20–40 hours per week, depending on the project

Nice to have

• Publications or open-source work on RL or agent environments
• Experience with Docker, sandboxed execution or distributed rollouts
• Familiarity with LLM post-training methods (PPO, GRPO, RLVR)

Work authorization: We support CPT, OPT and STEM OPT.

Compensation & benefits

• Stipend: $60–120 per hour
• Mentorship: Fellows receive direct mentorship from MatrAIx researchers and advisors, including 3 Nobel laureates, a Fields Medalist, and a Turing Award winner, alongside mentors with backgrounds as a former OpenAI senior director, an Anthropic researcher, a Google DeepMind senior research scientist, and faculty at Stanford University, Harvard University and MIT.
• Meals: Reimbursed up to $1,500 per month
• Path to full-time: Strong fellows may be considered for full-time roles.