I'm a research engineer at Prime Intellect based in San Francisco. I mostly work on leveraging inference-time compute for LLMs.

Before Prime Intellect, I co-founded Revideo (YC S23), an open source animation library. I studied physics at RWTH Aachen but dropped out in 2023. During my studies, I worked on a few things:

• I was one of the first engineers at Dynamo AI, working on federated learning across heterogenous data sources and ML on constrained hardware (e.g. mobile phones).
• I did research at the intersection of ML and (differential) privacy. Some of my work includes neighbourhood attacks, a membership inference attack against LLMs, and DP-VAE, a method for differentially private inference from variational autoencoders.

Outside of work, I like to be physically active! I practice and compete in grappling (no-gi BJJ), and I like to run and lift weights. In 2025, I want to learn surfing :)

Contact me: Feel free to email me (justus.mattern_at_rwth-aachen.de) or DM me on Twitter if you want to chat about my work or get a coffee!