Inferact is a Berkeley- and San Francisco-based AI infrastructure company founded by the creators and core maintainers of vLLM, the most widely used open-source engine for running large language models. The company commercializes vLLM - which at any moment powers inference on more than 400,000 GPUs worldwide - by funneling paid engineering resources back into the open project while building a next-generation commercial 'universal inference layer' meant to make AI inference cheaper and faster. Inferact launched publicly in January 2026 with a $150 million seed round at an $800 million valuation, co-led by Andreessen Horowitz and Lightspeed.
Simon Mo is the CEO and co-founder of Inferact, the startup commercializing vLLM, the open-source inference engine he helped create and now leads as lead maintainer. A PhD student at UC Berkeley's Sky Computing Lab advised by Ion Stoica and Joseph Gonzalez, Mo has spent roughly eight years building high-throughput, memory-efficient model-serving systems, from Ray Serve at Anyscale to vLLM, which now powers inference for companies including Amazon. In January 2026 he and his vLLM co-maintainers raised a $150M seed round at an $800M valuation, co-led by Andreessen Horowitz and Lightspeed.