Announcing our $800M Series C to accelerate the shift to open-source AI

Four years ago, my co-founders and I started Together AI because we saw generative AI as a turning point for human progress. We believed this generational technology should be open and abundantly available, not controlled by a handful of companies.

Since then, we have built a full-stack AI platform for open-source AI, grounded in frontier research and delivering the fastest and most efficient inference for AI applications and agents. Today, Together AI is trusted by thousands of customers, including many of the world's fastest-growing AI companies like Cognition, Decagon, Eleven Labs, Cursor, and Suno. What began as a conviction about the future of AI has grown faster than even our most optimistic projections.

Today, I am excited to announce the next milestone in our journey with Series C funding of $800 million from an incredible group of investors including Aramco Ventures, NVIDIA, Vista Equity, General Catalyst, Emergence Capital, Schneider Electric, Pegatron, Salesforce Ventures, March Capital, DTCP Growth, Lux Capital, Geodesic, PSP Partners, and others. In addition to the equity capital, we have secured commitments for over 500 MW of compute capacity to be capitalized independently by our new investors to support our expected compute growth in the coming years.

The economics of production AI

As AI systems begin to perform real intellectual labor, they are moving from occasional tools to core production infrastructure. Companies are no longer generating a handful of responses for a demo; they are deploying agents that write code, resolve customer issues, analyze documents, and automate entire workflows. As that work scales, so does the demand for inference.

Many companies are discovering that this creates a fundamental economic challenge. The cost structure of closed frontier LLMs that appears manageable in a prototype often becomes unsustainable in production. As usage grows, inference bills compound faster than budgets, forcing companies to ration intelligence just as demand for it accelerates. The most successful companies are responding the way markets always do: by finding a more efficient way to produce an increasingly essential resource.

Together AI has become the production platform for open and custom AI, combining frontier models with continuous innovation across the inference stack to deliver the best economics at scale. Open-weights models like DeepSeek, Nemotron, MiniMax, Kimi, and GLM have closed the quality gap with proprietary frontier models while giving developers the freedom to customize and fine-tune them for their own applications. As a result, companies building with open models routinely achieve 6x to 20x lower costs while maintaining equal or better performance. Decagon, for example, reduced its inference costs sixfold after moving to Together AI.

But the economics of production AI are not determined by models alone. They are determined by the full stack: models, kernels, compilers, inference systems, training infrastructure, hardware utilization, and the software that brings all of it together.

Together AI is a research-driven company. Over the past several quarters, our research-to-production pipeline has accelerated substantially. We announced FlashAttention-4 for NVIDIA Blackwell, Together Megakernel and together.compile to bring kernel-level optimization to production workloads, and expanded our post-training APIs to support tool calling, reasoning, and vision-language models. We launched the fastest endpoints for leading frontier open-source models and have become one of the largest producers of AI tokens in the world.

I am proud of the platform we have built that offers choice, control, advantaged economics, and frontier performance for the full-suite of generative AI production capabilities across inference, training, and accelerated compute, as well as the role that Together AI is playing in accelerating innovation and delivering the open-source AI ecosystem globally.

To our customers, team, and investors: thank you for believing in this vision and helping us bring it to life. This milestone is certainly worth celebrating, but it feels far more like a beginning. We remain in the earliest days of a technological transformation that will reshape every industry.

If our vision resonates with you, reach out — we are hiring across engineering, research, product, and go-to-market.