RadixArk is an AI infrastructure company spun out of the team behind SGLang, the open-source inference engine that serves trillions of tokens a day for the likes of Google, Microsoft, NVIDIA, Oracle and xAI. Founded by Ying Sheng and Banghua Zhu, RadixArk keeps SGLang and its reinforcement-learning framework Miles free and open while selling managed hosting and tooling on top, aiming to make building, training and running frontier models at least 10x cheaper and 10x more accessible. It launched publicly in May 2026 with a $100M seed round led by Accel and Spark Capital at a $400M valuation.
Ying Sheng is the co-founder and CEO of RadixArk, an AI infrastructure company that spun out of SGLang, the open-source inference engine she helped create in 2023. SGLang now runs across hundreds of thousands of GPUs and serves trillions of tokens a day for Google, Microsoft, NVIDIA, xAI and others. A Stanford computer science PhD and former xAI technical staff who co-led the inference team behind Grok, she launched RadixArk in May 2026 with $100 million in seed funding led by Accel at a $400 million valuation, on a mission to make frontier-level AI infrastructure open and accessible to everyone.