Together AI lands $800M Series C

Together AI has announced an $800 million Series C funding round, signaling a major push to accelerate the adoption of open-source artificial intelligence. The company aims to make AI intelligence abundant and cost-effective, challenging the economics of proprietary models.

The investment, led by Aramco Ventures and including NVIDIA, Vista Equity, and General Catalyst, underscores growing confidence in the open-source AI ecosystem. Together AI claims its platform delivers 31% more transactions per second (TPS) than the next fastest open-source engine for production coding agent workloads.

This substantial capital infusion, coupled with commitments for over 500 MW of compute capacity, will support Together AI's mission to provide a full-stack platform for open-source AI. The company emphasizes that as AI systems become core production infrastructure, the cost of inference with closed models becomes unsustainable. Companies are increasingly turning to open-weights models, which Together AI states can offer 6x to 20x lower costs with comparable or superior performance.

Customers like Decagon have already seen significant cost reductions, reportedly sixfold, after migrating to Together AI's platform. The company's strategy focuses on optimizing the entire inference stack, from models and kernels to compilers and hardware utilization.

Together AI highlighted recent advancements, including FlashAttention-4, Together Megakernel, and together.compile, alongside expanded post-training APIs for advanced AI capabilities. The company also noted the availability of on-demand NVIDIA B200 GPUs on its clusters and support for models like MiniMax-M3.

The push for open-source AI is gaining momentum, with models like DeepSeek, Nemotron, MiniMax, Kimi, and GLM closing the quality gap with proprietary alternatives. This trend allows developers greater freedom to customize and fine-tune models for specific applications, a critical factor for production AI. The company's platform now supports over 40 models chosen for production use cases.

This funding round positions Together AI to further solidify its role in democratizing AI development and deployment. The company views this milestone as a beginning, anticipating continued transformation across industries driven by open AI innovation.