What Is Together AI? Together AI is an AI inference platform that hosts hundreds of open-source models behind one OpenAI-compatible API. Founded in 2022 and backed by NVIDIA, Salesforce Ventures, and Kleiner Perkins, the company built its reputation around two things developers actually care about: fast hosted inference for state-of-the-art open models (Llama, DeepSeek, Qwen, Mixtral) and a genuinely free tier that exposes a small but useful set of those models with no credit card required. What separates Together AI from the long list of “free AI API” providers in 2026 is the breadth of categories you can hit on a single key.…