The open-source AI tool SGLang, utilized by companies like xAI and Cursor for accelerating AI model training, has seen a portion of its maintenance team transition to a new commercial startup named RadixArk. Originating from UC Berkeley's lab in 2023, RadixArk was recently valued at approximately $400 million in a round reportedly led by Accel, with prior angel investment from figures like Intel CEO Lip-Bu Tan. Ying Sheng, a key SGLang contributor and former xAI engineer, is now the co-founder and CEO of RadixArk, which, like SGLang, focuses on optimizing AI model inference processing to enhance speed and efficiency on existing hardware, a critical area for reducing AI service costs.