Moonshot AI launches Kimi K3, the world’s largest open‑weight AI model

Chinese startup Moonshot AI unveiled Kimi K3, a 2.8‑trillion‑parameter language model that it calls the world’s largest open‑weight AI system. The model offers a 1‑million‑token context window and is optimized for advanced reasoning, long‑horizon coding and knowledge‑work tasks. Independent benchmarks place Kimi K3 close to leading U.S. models such as Anthropic’s Fable 5, OpenAI’s GPT‑5.6 and GPT‑5.5, while it topped Arena.ai’s frontend‑code leaderboard, surpassing Claude Fable 5. The model’s weights will be released publicly on 27 July 2026. Backed by Alibaba and Tencent, Moonshot highlights two architectural upgrades that improve compute efficiency and enable minimal‑human‑supervision coding. The launch follows a rapid release cycle in China’s AI sector, narrowing the performance gap with U.S. frontier models and raising competitive, cost and policy implications for global AI developers.