Kimi K3: The Open-Weight Model That Finally Hit Frontier

On July 27, 2026, Moonshot AI released Kimi K3, a 2.8-trillion-parameter Mixture-of-Experts model, which became the first open-weight model to top the Artificial Analysis Intelligence Index, tying with closed-source flagships. The model activates only 104 billion parameters per token, marking a significant milestone for open-weight AI performance.

Open-weight models have been chasing frontier performance for two years. On July 27, 2026, Moonshot AI closed the gap. Kimi K3, a 2.8-trillion-parameter Mixture-of-Experts model, became the first open-weight model to reach the top of the Artificial Analysis Intelligence Index — tied for first with the closed-source flagships. If you have been waiting for “open weights but actually good,” this is the moment. What Kimi K3 Actually Is The headline number — 2.8 trillion parameters — obscures more than it reveals. K3 is a sparse MoE model, meaning only 104 billion parameters are active on any given token. Underneath that … The post