Justus Mattern is a co-founder at Proximal, where he works on reinforcement-learning environments, coding agents, and post-training data for frontier AI systems. Previously, he built open-source reinforcement-learning infrastructure at Prime Intellect and co-founded Revideo, an open-source animation library. He has also worked on privacy-preserving machine learning and federated learning.
Justus Mattern is a co-founder at Proximal, where he works on reinforcement-learning environments, coding agents, and post-training data for frontier AI systems. Previously, he built open-source reinforcement-learning infrastructure at Prime Intellect and co-founded Revideo, an open-source animation library. He has also worked on privacy-preserving machine learning and federated learning.
Career
Justus Mattern studied at RWTH Aachen University (Physics studies; did not complete degree).
Co-Founder at Proximal until Present