Moonshot Releases Kimi K3.1 Pro, Open-Weight Model Closing Gap With Claude Opus

Moonshot AI has released Kimi K3.1 Pro, a 2.8-trillion-parameter open-weight model that positions itself as a serious challenger to Claude Opus 5.5, ranking fourth globally on capability benchmarks. The model, launched October 23–24, 2026, features a 1-million-token context window and becomes available immediately across Kimi.ai, mobile apps, and the API at $2/$10 per million tokens—33% cheaper than its predecessor.