What is kimi k3?

Kimi K3 is an open-weight frontier model that, as of mid-2026, was noted as the first open model to surpass all proprietary ones on a comprehensive web engineering benchmark. It is also the first open-weight model of its size, though it uses over twice the tokens and costs around 40% more per task for a slightly lower intelligence index score than some alternatives.

• Jul 2026 - Nathaniel Whittemore said Kimi K3 is the first open model ahead of all proprietary ones on a comprehensive web engineering benchmark.
• Jul 2026 - Nathaniel Whittemore stated it is the first open-weight model of its size.
• Jul 2026 - Guillermo Rauch said Kimi K3 is the best performing model ahead of Fable, reaching a comparable success rate in less time.
• Jul 2026 - McCoy noted Kimi K3 is a true open-weights frontier model, making fine-tuning for malicious purposes trivial.
• Jul 2026 - Henry reported K3 uses over twice the tokens and costs around 40% more per task for a slightly lower AA intelligence index score.