Kimi K3.1 Pro: developer tools for developers

What it does

Moonshot describes K3.1 Pro as a post-trained version of Kimi K3 and its most capable 3T-class open-weight model. Moonshot reports 65.7% on Terminal-Bench 4.0, narrowly behind Claude Opus 5.5 at 66.4% (vendor-reported, not independently verified). Moonshot also says it removed cyber-related training data for the open-weight release.

Official site:www.kimi.ai.

Editorial note

Kimi K3.1 Pro is Moonshot AI’s new flagship model. Moonshot says it has a 1-million-token context window, a Highspeed version that runs 2-3x faster, and full weights coming by November 4, 2026.

Who it’s for

• For: Developers who want a long-context coding model that will also ship as open weights.
• Not ideal for: people who need independently verified benchmark results before choosing a model.

Key use cases

• Build apps & code
• Research & answers

What you can do with it

• Free access: Moonshot says K3.1 Pro is available on Kimi.ai, the Kimi apps, Kimi Work, Kimi Code and the Kimi API; plan prices were not checked for this page. This matters when you want to test before you pay.
• Kimi API plan: Models kimi-k3.1-pro and kimi-k3.1-pro-highspeed; Zero Data Retention available, per Moonshot. This matters when the free tier is not enough.
• Open weights plan: Moonshot says full weights will be released by Nov 4, 2026. This matters when the free tier is not enough.
• Help documentation: Official pricing and product pages at www.kimi.ai. This matters when you set it up yourself.