Together AI raises $800M Series C at $8.3B valuation; open-source inference hits $1.15B bookings

Together AI, a San Francisco-based AI cloud provider, closed an $800 million Series C funding round on July 1, 2026, at an $8.3 billion post-money valuation. The round was led by Aramco Ventures and included participation from Vista Equity Partners, General Catalyst, Emergence Capital, NVIDIA, Salesforce Ventures, March Capital, Pegatron, and SentinelOne's S Ventures, among others. Together AI reported annual bookings exceeding $1.15 billion in its most recent quarter, making it one of the few standalone AI infrastructure companies to reach enterprise-scale revenue.

Together AI combines open-source models with high-performance infrastructure and research to facilitate efficient, large-scale AI training, inference, and reinforcement learning for developers and enterprises. The company plans to use the new funding to expand its products and scale its capacity and infrastructure footprint, which it expects to grow roughly 50-fold over the next five years. The investment validates a broader market shift: open-weight AI inference has crossed from experimental alternative to production infrastructure. Aramco's lead investment signals Saudi Arabia's interest in securing long-term compute capacity as part of national AI sovereignty strategy.

For engineering teams evaluating AI inference platforms, Together AI's scale and valuation leap (from $3.3B to $8.3B in 16 months) reflect growing confidence in open-source models as cost-competitive alternatives to closed frontier APIs. With bookings nearing $1.2B annualized, the company is now a viable production dependency for enterprises seeking to reduce per-inference costs. The 50x infrastructure expansion plan also signals capacity-planning shifts across the inference-heavy AI stack over 2026-2030.