RadixArk Launches with $100M Seed at $400M Valuation to Build on SGLang Inference Engine
Tags AI · Infrastructure · OSS
RadixArk, founded by the creators and core maintainers of the open-source SGLang inference engine, launched with $100 million in seed funding at a $400 million post-money valuation. The round was led by Accel and Spark Capital, with participation from NVIDIA's NVentures, AMD, Intel CEO Lip-Bu Tan, Broadcom CEO Hock Tan, OpenAI co-founder John Schulman, and PyTorch creator Soumith Chintala. SGLang serves trillions of tokens daily for Google, Microsoft, NVIDIA, Oracle, AMD, Nebius, LinkedIn, xAI, and others. RadixArk is building an end-to-end AI infrastructure platform treating inference, training, and post-training as first-class citizens.
Technical significance
A $100 million seed round at a $400 million valuation is extraordinary, reflecting investor conviction that AI infrastructure — not just models — is where the value will accrue. SGLang's position as the inference engine for major AI companies gives RadixArk a unique starting point. The investor roster (NVIDIA, AMD, Intel, OpenAI, PyTorch) reads like a who's who of the AI stack, suggesting broad industry alignment behind the thesis.