MatrAIx Fellow, User Simulation & Synthetic Data

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 working on LLMs, NLP or user modeling who want to apply their research to real-world agent systems, and industry engineers or researchers who want to work on user simulation and synthetic data research and development.

In this track, you'll build and evaluate realistic user simulations to support MatrAIx's agent training and evaluation: how to keep user behavior consistent over long conversations, how to measure whether a simulation is realistic, and whether the data it produces actually improves agents.

What you'll do

• Scope your project with your MatrAIx mentor
• Build or extend LLM-powered simulated users for multi-turn interactions
• Design experiments that measure realism, consistency and diversity
• Test whether simulation-generated data improves agent training or evaluation
• 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, NLP or a related field
• Strong grounding in LLMs and generative modeling
• Fluent in Python; experience with PyTorch or JAX
• Hands-on experience with an LLM application, simulation or dataset project
• Able to commit 20–40 hours per week, depending on the project

Nice to have

• Research in user simulation, generative agents or multi-agent systems
• Experience with preference data, RLHF or post-training
• Publications in NLP, generative AI or synthetic data

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.