Together AI

Together AI is a cloud platform purpose-built for running and fine-tuning open-source large language and generative models at production scale, giving developers an alternative to closed, proprietary model APIs. It offers inference endpoints for popular open-weight models, along with tools for fine-tuning those models on proprietary data and dedicated GPU clusters for teams running heavy training or inference workloads. Together AI's inference stack is optimized specifically for throughput and latency on open models, which lets teams serve chat, coding, and retrieval-augmented generation applications at a fraction of the cost of comparable closed-model APIs while retaining more control over the underlying weights. The platform supports the full lifecycle a startup needs when building on open-source AI: browsing and testing models, fine-tuning on custom datasets, deploying dedicated or serverless endpoints, and monitoring usage and cost as traffic scales. Together AI is aimed at engineering teams who want the flexibility of open-source models, including the ability to self-host or migrate later, without having to build and operate their own GPU infrastructure from day one. It has become a common backend choice for AI startups building chat products, coding assistants, and retrieval systems that need reliable, cost-efficient access to leading open models without negotiating enterprise contracts with the largest foundation model labs.