A New Era of AI Infrastructure: Open Source Tools Turned Venture-Backed Startups
There is a noticeable trend in the AI infrastructure landscape where popular open source tools are evolving into venture-backed startups valued at hundreds of millions of dollars. The most recent example is RadixArk, the commercial entity behind SGLang, a tool gaining traction for optimizing AI model performance in terms of speed and cost efficiency.
Rumored to be valued at around $400 million in a recent funding round led by Accel, RadixArk has quickly garnered attention despite being announced just last August. While the exact funding amount remains unconfirmed, the growth trajectory of the startup is undeniable.
The roots of RadixArk can be traced back to SGLang, a tool developed in 2023 within the UC Berkeley lab of Ion Stoica, co-founder of Databricks. Notable companies like xAI and Cursor have embraced SGLang to enhance AI model training, prompting key members of the SGLang team to transition to RadixArk as a commercial venture.
One such figure is Ying Sheng, a former xAI engineer and now the co-founder and CEO of RadixArk. Sheng’s expertise in AI research, coupled with her background at Databricks, positions her as a driving force behind the startup’s growth. Investors, including Intel CEO Lip-Bu Tan, have shown early support for RadixArk’s mission.
RadixArk’s focus on optimizing inference processing, along with model training, addresses a significant cost factor in AI services. By enabling models to operate more efficiently on existing hardware, RadixArk and SGLang offer immediate cost savings to businesses deploying AI solutions.
The Rise of vLLM and the Inference Optimization Landscape
In a parallel development, vLLM, a project incubated in Ion Stoica’s UC Berkeley lab, has also emerged as a well-funded startup targeting inference optimization. Reports suggest that vLLM is in talks to secure substantial funding, with prominent venture capital firm Andreessen Horowitz potentially leading the investment charge.
Despite some discrepancies in reported figures, the transition of both SGLang and vLLM from open source projects to fully-fledged startups underscores the industry’s recognition of the value in optimizing the inference layer of AI systems. Large tech companies have already adopted these tools for their inference workloads, signaling a shift towards more efficient AI operations.
RadixArk remains committed to advancing SGLang as an open source AI model engine, while also introducing Miles, a specialized framework for reinforcement learning. By offering hosting services for a fee, RadixArk aims to sustain its growth and innovation in the AI infrastructure space.
Investment Surge in Inference Infrastructure
The surge in funding for startups specializing in inference infrastructure highlights the critical role this layer plays in AI development. Companies like Baseten and Fireworks AI have secured significant investments, signaling the industry’s confidence in the future of AI optimization.
As RadixArk and other ventures continue to bridge the gap between open source innovation and commercial viability, the AI infrastructure landscape is poised for further evolution and growth.

