Together AI Raises $800 Million at an $8.3 Billion Valuation to Power the Open-Source AI Stack

Together AI, the San Francisco startup that has built its business on making open-source AI models cheaper and faster to run than their closed-source rivals, has raised an $800 million Series C at an $8.3 billion post-money valuation — more than doubling the $3.3 billion price tag it carried just sixteen months ago. The round, announced July 1, 2026, was led by Aramco Ventures, with participation from Vista Equity Partners, General Catalyst, Emergence Capital, Nvidia, March Capital, Pegatron, and SentinelOne's S Ventures, among others.

The financing lands at a moment when the economics of building with AI have become impossible to ignore. Frontier-model pricing from closed providers can consume a startup's entire margin, and Together AI has positioned itself as the infrastructure layer for the alternative: training and running workloads on open models such as DeepSeek, Nemotron, MiniMax, and Kimi at a fraction of the cost of closed systems, with what the company says is comparable or better performance.

"Intelligence is becoming a foundational resource for the modern economy, every bit as essential as electricity, bandwidth or capital," said Vipul Ved Prakash, Together AI's co-founder and CEO, in the company's funding announcement. "Our mission is to ensure that intelligence is abundant, not expensive. The future of AI won't be owned by a few companies. It will be built by millions of developers and businesses, and open-source models are making that possible."

The numbers behind the raise are striking. Together AI's annual bookings crossed $1.15 billion last quarter, the company said, as open-source model usage across the industry has tripled over the past twelve months, according to data the company cited from AI gateway OpenRouter. Together AI now counts thousands of paying customers, including Cursor, Cognition, and Decagon, with customers reporting cost savings of 6x to 60x compared with closed-model pricing for equal or better performance. Decagon, for instance, said it cut its inference costs sixfold after moving workloads onto Together's platform. Nearly three-quarters of organizations expect to increase their use of open-source AI, according to research from McKinsey cited in the announcement.

The company, founded in 2022 by Prakash alongside Stanford professor Percy Liang and Ce Zhang, an associate professor at ETH Zurich and the University of Chicago, plans to use the new capital to expand its product lineup and dramatically scale its computing capacity — infrastructure it expects to grow roughly 50-fold over the next five years. The Series C follows a $305 million Series B that valued the company at $3.3 billion in February 2025, and a $102.5 million Series A led by Kleiner Perkins in 2023. Reports from The Information in March had suggested Together AI was seeking $1 billion at a $7.5 billion valuation, meaning the company ultimately raised less capital than rumored but landed a higher valuation than the figure that had circulated months earlier.

Aramco Ventures' role as lead investor underscores a broader pattern of energy and industrial capital flowing into AI infrastructure. "Building AI infrastructure over the next decade will be the biggest infrastructure project in human history," said Abhishek Shukla, managing director of Prosperity7 Ventures US, Aramco Ventures' diversified venturing program. "Together has built the platform that makes open source models genuinely usable at enterprise scale, and the team's ambition matches the scale of the opportunity in front of them. We're proud to partner with them, not just on this round but on scaling compute and capacity globally." Meshal Almashari, Aramco Ventures' executive managing director for late-stage venturing, added that the investment "reflects our long-term conviction in artificial intelligence infrastructure and the platforms that will enable AI deployment at scale." Schneider Electric CEO Olivier Blum, whose company invested through its SE Ventures fund, framed the deal through an energy lens, noting that "AI and energy infrastructure are converging, and efficiency is the link between them."

Why It Matters

Together AI's raise is a data point in a much larger shift: enterprises that once defaulted to closed frontier models from OpenAI or Anthropic are increasingly routing workloads to open-weight models hosted on specialized "neocloud" infrastructure, chasing dramatically lower per-token costs without giving up much on quality. The tripling of open-source model usage industry-wide in twelve months, and Together AI's jump past $1.15 billion in annual bookings, suggest this is no longer a niche cost-optimization play for budget-constrained startups — it is becoming a default architecture choice. Emergence Capital's Joe Floyd put it bluntly in the company's announcement: "The shift toward open source isn't a niche preference anymore, it's becoming the default for any company that wants to scale AI without losing its margin." The involvement of Aramco Ventures and Schneider Electric also signals that traditional energy and industrial players see AI compute demand as a durable, capital-intensive market worth entering directly, not just powering from the sidelines. Together AI is not alone in attracting this kind of capital — GPU-focused neoclouds Upscale AI and TensorWave each closed nine-figure rounds in the weeks before Together's announcement — suggesting investors are betting heavily that the infrastructure layer beneath open models, not just the models themselves, is where durable value will accrue.

What to Watch

The real test for Together AI will be whether its bookings growth holds up as competition among neocloud providers intensifies and as hyperscalers like AWS, Google Cloud, and Microsoft Azure push harder into open-model hosting themselves. Watch for how quickly the company can execute on its promised 50-fold infrastructure expansion, whether it can maintain the 6x-to-60x cost advantage it's advertising to customers as GPU supply and pricing shift, and whether Aramco Ventures' involvement leads to concrete announcements on global compute and energy partnerships. With annual bookings already above $1.15 billion, an IPO or further mega-round within the next two to three years is a plausible next chapter if growth continues at its current pace.