# Simon Mo

> 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.

- **Role:** CEO and Co-Founder at Inferact
- **Organizations:** Inferact, vLLM Project, UC Berkeley Sky Computing Lab, PyTorch Foundation, Anyscale (former), Character.AI (former)
- **Education:** PhD student, Electrical Engineering & Computer Sciences (Sky Computing Lab), University of California, Berkeley, Computer Science, Mathematics, and Philosophy, University of California, Berkeley
- **Known for:** Lead maintainer of vLLM, an open-source LLM inference engine with 83k+ GitHub stars, now stewarded by the PyTorch Foundation, Co-founded Inferact and raised a $150M seed round at an $800M valuation, Helped build Ray Serve from zero to one at Anyscale

## Career timeline

- **2021** — Software engineer at Anyscale working on Ray Serve; speaks at PyCon 2021 on 'Patterns of ML Models in Production'
- **2023** — Co-creates vLLM at UC Berkeley's Sky Computing Lab; hosts the first vLLM community meetup
- **2024** — vLLM named one of the first Sequoia Open Source Fellows
- **2025** — Co-founds Inferact (November) with vLLM co-maintainers; gives PyTorch Conference keynote on vLLM updates
- **2026** — Inferact emerges from stealth with a $150M seed round at an $800M valuation, co-led by a16z and Lightspeed

## Achievements

- Lead maintainer of vLLM, an open-source LLM inference engine with 83k+ GitHub stars, now stewarded by the PyTorch Foundation
- Co-founded Inferact and raised a $150M seed round at an $800M valuation
- Helped build Ray Serve from zero to one at Anyscale
- Named a 2024 Sequoia Open Source Fellow for vLLM
- Delivered a PyTorch Conference 2025 keynote on vLLM
- Contributed across the Ray, Modin, and Clipper open-source projects

## Latest updates

- **2026-01** — Inferact emerged from stealth with a $150M seed round at an $800M valuation, co-led by Andreessen Horowitz and Lightspeed, to commercialize vLLM.

## Links

- Website: https://inferact.ai
- LinkedIn: http://www.linkedin.com/in/simon-mo-834217162
- Twitter/X: https://x.com/simon_mo_
- GitHub: https://github.com/simon-mo

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Profile page: https://yespress.io/simon-mo
Published by YesPress — https://yespress.io
Last updated: 2026-06-21