Moonshot AI Kimi K3: World's Largest Open-Source AI Model

Chinese startup Moonshot AI has released Kimi K3, which it calls the world's largest open-source AI model. This Beijing-based company unveiled Kimi K3 this week. The model contains 2.8 trillion parameters. This makes it roughly 75% larger than DeepSeek's V4 Pro, a previous large Chinese open-weight model. Kimi K3 is also about 2.8 times the size of Moonshot's earlier K2.6 model. Moonshot states K3 performs competitively against Anthropic's Fable 5 and substantially outperformed Anthropic's Opus 4.8, as well as OpenAI's GPT 5.6 Sol and GPT 5.5, on company benchmarks. One independent benchmark reportedly ranked K3 as the best-performing model available. K3 is Moonshot AI's most powerful open-source coding model. It features Kimi Delta Attention and Attention Residuals, two new architectural innovations. It also supports a 1-million-token context window and has native visual understanding capabilities. The API is compatible with the OpenAI SDK. This development could significantly impact the global artificial intelligence landscape.