Together AI, the company making it dramatically cheaper and easier to run open source AI models at scale, raised $800 million in a Series C funding round at an $8.3 billion post-money valuation.
The funding round was led by Aramco Ventures, with participation from Vista Equity Partners, General Catalyst, Emergence Capital, NVIDIA, March Capital, Pegatron, S Ventures (SentinelOne), and others.
Together AI has emerged as the infrastructure layer for the alternative — helping companies train and run workloads on open models like DeepSeek, Nemotron, MiniMax, and Kimi at a fraction of the cost of closed systems, with comparable or better performance.
Together AI’s annual bookings crossed $1.15 billion last quarter, as open-source model usage across the industry has tripled in twelve months. The company now serves thousands of paying customers, including many of the biggest names in AI like Cursor, Cognition, and Decagon. Customers report cost savings of 6x to 60x compared to closed-model pricing for equal or better performance — Decagon, for example, cut inference costs sixfold after moving to Together. It’s no surprise that nearly three-quarters of organizations expect to increase their use of open-source AI, according to McKinsey.
Together AI said it will use the new funding to expand its products and features as it becomes a leading provider of inference, and to dramatically scale its capacity and infrastructure footprint, which the company expects to grow roughly 50-fold over the next five years.