RadixArk Spins Out from Project SGLang at $400M Valuation: How AI Inference Is Reshaping Tech Investment

RadixArk Spins Out from Project SGLang at $400M Valuation: How AI Inference Is Reshaping Tech Investment

You know what’s wild? A startup company barely six months old just got valued at $400 million. We’re not talking about some consumer-level app with millions of users at once – this is RadixArk, a company millions haven’t even heard about. But here’s the thing: they’re tackling one of the biggest headaches for AI, and investors can’t throw money at them fast enough.

Project SGLang spins out as RadixArk $400M valuation at $400M valuation as inference market explodes – that sounds like some geek speak for you, but that’s actually a pretty big deal. Think of it this way: Training an AI model is like teaching someone to cook. Inference is them actually making a dinner every single night. And right now, those nightly dinners are costing companies a real penance.

RadixArk, a company that supports the artificial intelligence field and companies by creating AI models that are faster and cheaper on the same hardware, has come out of UC Berkeley’s famous artificial intelligence laboratories. In an industry where every millisecond and every dollar is important, that is kind of a superpower.

The Story Behind RadixArk’s Lightning Fast Rise

Here is where this gets interesting. RadixArk didn’t begin in someone’s garage – it emerged from SGLang, an open-source project that was silently becoming infrastructure critical to AI companies. The project was born in 2023 inside the UC Berkeley lab of Ion Stoica, you know, the cofounder of Databricks. Yeah, he is almost like a serial startup wizard.

Ying Sheng, who ireviously working at Elon Musk’s xAI (you know, the company behind Grok), decided to leave in August 2025 to become RadixArk’s co-founder and CEO. She’d been an important contributor to SGLang and saw something huge brewing. According to her LinkedIn announcement, she left xAI – a place where she’d built “deep emotions and countless beautiful memories” – to wager on this vision.

The funding round was led by Silicon Valley’s Accel, one of the most respected venture capital firms. They’ve backed companies such as Facebook, Slack, and Dropbox, so they’re hardly rookies as far as determining who’s going to be a winner. RadixArk also attracted the early attention of Intel CEO Lip-Bu Tan in terms of angel investment, so that’s telling you something as to how serious the tech industry is taking this.

What Does RadixArk’s Exactly What Is It? (And Why It Matters)

Let’s break this down without the buzzwords. When you use ChatGPT or Claude or any AI tool, then there basically, I guess these arebasically  two phases:

  1. Training: Training the AI model (super expensive, 1-time)
  2. Inference: Is that something that you actually get AI to answer your questions? (happens constantly, adds up fast)

Most of the focus of the industry has been on training. But as OpenAI reportedly spends over 25% of their Sora video generator’s revenue just on the costs of inference, which they’ve called “completely unsustainable”, companies are realizing they’ve got a problem.

AI inference optimization is what RadixArk comes in to do. Their tech, which is based on the software SGLang, assists AI models in processing information faster using less computing power. Major players such as xAI and Cursor are using it to speed up their operations already.

The secret sauce? Something called RadixAttention – a trick that does recycling computation work in which the AI asks multiple, but instead of starting from scratch every single time. It’s as if your brain could remember that in a math problem,m it had already performed the first half and just work out the new part – instead of doing it all over again.

The Booming AI Inference Market | Artificial Intelligence Essay Database No 1

The numbers here are really kinda staggering as a whole. According to several market research companies:

  • The total value of the global AI inference market was valued to be worth around $97 – $106 billion in the year 2024
  • It’s projected to be at $254-255 billion by 2030
  • That is a compound annual growth rate (CAGR) of around 17-19%

To put that in perspective, we are talking about an industry that’s more than doubling in size in a short 6-year period. And it makes sense – every time someone uses an AI chatbot, generates an image,e or gets a personalised recommendation, that’s an inference request somewhere.

Companies like Baseten have just raised $300 million at a $5 billion valuation. Fireworks AI pulled in $250 million at $4 billion. The market is absolutely exploding, and the infrastructure providers who can cut those costs are good as gold (or maybe GPU chips, but they might be more valuable right now).

RadixArk vs. vs. vLLM: The War for AI Inference Supremacy

RadixArk is not waging this war currently alone. Their biggest competitor is probably vLLM, another UC Berkeley spinout which has been around a bit longer. In December 2025, Forbes reported that vLLM was in talks to raise at least $160-million at a valuation of $1-billion (Andreessen Horowitz reportedly spearheaded the round).

Both companies emerged from Ion Stoica’s lab at Berkeley. The focus of both is to make AI inference faster and cheaper. They are both riding the same huge wave. But, there are some differences: Both tools remain at a largely open-source state, which is interesting. They’re betting they can build massive businesses on top of free software, like how Red Hat became a multi-billion dollar company bearing the name of Linux around which it sold services.

FeatureRadixArk (SGLang)vLLM
Current Valuation~$400 million~$1 billion (reported)
Lead InvestorAccelAndreessen Horowitz (reported)
CEO BackgroundYing Sheng (ex-xAI, Databricks)Simon Mo
Key TechnologyRadixAttention, Miles frameworkPagedAttention memory optimization
Primary UsersxAI, CursorMultiple hyperscale companies
CommercializationHosting fees + managed servicesStill developing strategy

Open Source to Unicorn Pipeline

There’s a situation emerging here, a pattern that’s worth paying attention to. Popular open-source AI tools are turning into hundreds of millions of dollars worth of venture-backed startups almost overnight. It’s happening with:

  • RadixArk ($400M valuation)
  • vLLM (~$1B valuation)
  • Hugging Face (multi-billion-dollar valuation)

Why? Well, open source results in trust and acceptance. Developers test it, companies rely on it, and now there’s a huge installed base that requires an enterprise support system, managed hosting, nd custom solutions. That’s where there’s money to be had.

RadixArk is continuing to build on SGLang as an open source AI model engine and is building commercial products on top. They’re also working on Miles, a special thought framework that deals with reinforcement learning needs to help the AI models get smarter as time goes by, with continuous training.

What This Means for the Enterprise When It Comes to AI Implementation

If you’re operating with an AI business currently, you’re likely dealing with the cost of inference. Some rough numbers to think about:

  • Running Big language model queries can cost between $0.001 to $0.10 per request
  • At scale, that works out to millions a month
  • Reducing inference time to half can literally be a 50% reduction in your infrastructure cost

That is why companies are paying attention to solutions such as RadixArk. When the cost of your AI is up in the six or seven-figure range a month, the chance at a 40-60% improvement in performance is more than ‘nice to have’ – it’s potentially make or break for your business model.

The move towards edge computing and localised AI inference will also be changing things. Instead of routing all requests to huge data centers, companies are beginning to operate smaller models that are closer to users. This lowers latency (nobody likes waiting), enhances privacy, and can greatly reduce the cost in bandwidth.

The Bigger Picture: It’s Inferior Eating Up AI’s Lunch

Here is something that may perhaps surprise you: based onthe needs of delivering Deloitte predictions, inference workloads will account for approximately two-thirds of all AI compute in 2026, an increase from about a third in 2023. The market for inference-optimized chips alone is predicted to be more than $50 billion in 2026.

We’re seeing a fundamental change. Training was the expensive part — now it’s the day-in and day-out operation that’s eating budgets. And this provides opportunities for companies such as RadixArk that can optimize that ongoing cost.

Major cloud providers are paying attention:

  • According to Amazon Web Services, its Bedrock inference engine is already a “multibillion dollar business.”
  • Google is investing more and more into TPUs (Tensor Processing Units) that are tailored for inference.
  • Microsoft is increasing its purchase of general-purpose servers specifically to handle Copilot inference traffic

It is in the infrastructure layer that the real value is actually being created right now. Share post on LinkedIn by Yggy still, all without having any actors first for you/human assistance; “there may be flashy AI apps consumers, everything you see in the AI application plumbing underneath is making them all work efficiently.”

Challenges Yet to Come for RadixArk

It’s not all smooth sailing, obviously. RadixArk has some challenges facing it:

Competition is fierce. Outside of vLLM, there’s Baseten, Fireworks AI, and dozens of other start-ups that are going at the same problem. Plus, the main cloud vendors aren’t sitting on their hands and doing nothing – they’re building their own optimisation tools.

Monetization is tricky. Most of SGLang is Free and Open Source software. RadixArk is beginning to charge for hosting services, but it can be a balancing act to determine just the right balance between what is open and what’s paid.

The technology is changing rapidly. What works today may be obsolete in 18 months. Staying ahead requires constant innovation and investment in R&D.

Some customer education is required. Many companies lack a proper understanding of their inference costs or the potential savings. RadixArk needs to evangelize the problem and titssolution.

That said, though, having $400 million for support and serious tech talent, they’re in a pretty good position to solve these problems.

What Is Next: The Future of the AI Infrastructure

Looking into the future, there are a couple of trends that seem pretty clear:

More open source companies will spin out. The Berkeley model of incubating projects in academic labs and then commercializing them is working too well to stop now.

Inference optimization will continue to be very important. As AI becomes more widespread, the companies that can save those ongoing costs will capture huge value.

Consolidation is likely. Not all inference startupscano survive long-term. Expect acquisitions, mergers, and some failures along with the successes.

Edge AI will grow. Running models on devices and at the edge, instead of on centralized data centers, will become of growing importance.

RadixArk seems aware of this. Their long-term vision, according to their website, is “a world where every serious AI builder has access to infrastructure as fast, affordable, and reliable as anything inside the largest companies.” They’re seeking to make frontier-level AI infrastructure “10x cheaper and 10x more accessible.”

That’s ambitious. But then again, so was valuing a six-month-old startup at $400 million.

Conclusion

Project SGLang spins out as RadixArk at $400M valuation as inference market explodes — and honestly, there is something here that is critical about where AI is going. We’re beyond the cool factor of “wow, AI can do cool things” and into the infrastructure of “how do we make this work at scale without going broke?”

RadixArk might’ve just got started, but they’d be tackling one of the most important bottlenecks for the industry. With the help of proven technology, serious support,t and a team of some of AI’s sharpest minds, they’re set up to ride the boom of AI inference markets all the way up.

Will they succeed? That’s still being written. But if you’re paying attention to the direction AI infrastructure is heading, then RadixArk is certainly a name you’ll want to watch out for. The race for creating AI that can become faster, cheaper, and more accessible is only just beginning – and it’s going to change the way we all interact with technology.

Frequently Asked Questions (FAQs)

Q1: What is RadixAr,k, and how has it been different from other AI companies? 

A: RadixArk is an AI infrastructure company that was launched out of the open source SGLang project atUC Berkeleyy. Unlike companies developing AI applications, RadixArk specializes in ensuring existing AI models are running faster and cheaper as a result of inference optimization. They introduce techniques such as RadixAttention to lower computational cost without making any overthrows in performance.

Q2: Why is Artificial Intelligence Inferrence Optimization important at this point? 

A: With this explosion of AI adoption comes massive spending on what is known as inference – the continual cost of demarcation of AI models to respond to user requests. Some companies have reported inference costs which are upwards of 25% of revenue, thus unsustainable. Optimization tools can reduce such costs by 40-60%, making or breaking business models.

Q3: How does RadixArk make money as SGLang is open source? 

A: RadixArk takes a similar approach to companies such as Red Hat and MongoDB — they have oan pen source version of core technology, but they also charge for managed hosting service, enterprise support, and other commercial tools. They’re also working on Miles, a bespoke reinforcement learning framework that complements their inference offerings.

Q4: Which companies are already using SGLang technology? 

A: Some of the major tech companies that have affirmed their use of SGLang foraccelerating their AI business operations include xAI (Elon Musk’s AI company), and also Cursor (AI coding assistant). Several large technology companies also operate inference workloads using the system, but not all of them publicly reveal what they use for their infrastructure.

Q5: Is the $400 million valuation worth it for such a young company?

A: Although RadixArk has not been around for a year, the valuation is based on several factors – explosive growth in the AI inference market (expected to reach $255 billion by 2030), proven technology with established users, support from the best in venture capital firms such as Accel, and a team with extensive experience from xAI, Databricks and UC Berkeley. Similar companies such as vLLM and Baseten have even commanded even greater valuations.

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