Moonshot AI Launches Kimi K3, a 2.8-Trillion-Parameter Open AI Model

Beijing-based Moonshot AI has unveiled Kimi K3, a 2.8-trillion-parameter mixture-of-experts model it claims is the world's first open '3T-class' AI system. The model features a 1-million-token context window, native support for text, image, and video inputs, and a new architecture combining Kimi Delta Attention and Attention Residuals for improved efficiency. Moonshot says K3 is priced at roughly half the cost of rivals Claude Fable 5 and GPT-5.6 Sol, positioning it as a direct competitor to those frontier models. Developers can currently access K3 through kimi.com and the Kimi API, while full open-source model weights are scheduled for release by July 27, 2026. In benchmark testing, K3 leads on Program Bench and SWE Marathon but trails Claude Fable 5 on FrontierSWE and DeepSWE evaluations.