Kimi K3.1 Pro: a 3T-class 1M-context model at $2 per million input tokens, weights due by Nov 4
What is it?
Kimi K3.1 Pro is a post-trained version of Moonshot AI's K3, a 3T-class mixture-of-experts (MoE) model. It has 2.8T total parameters with 104B active per token, a 1M-token context window, and takes text and images as input. A Highspeed variant that runs 2-3x faster shipped alongside it, and both are live today in the Kimi app, Kimi Code, and the Kimi API under the model name kimi-k3.1-pro.
Why does it matter?
Moonshot reports 65.7%Vendor claim on Terminal-Bench 4.0, ahead of GPT-6 Astra (58.2%)Vendor claim and just behind Claude Opus 5.5 (66.4%)Vendor claim. API pricing drops to $2 per million input tokens and $10 per million output tokens, cheaper than K3. Once the weights land, teams get another frontier-level coding agent model they can host themselves. Moonshot also says it stripped cyberattack-related data from training to keep the model's hacking ability from growing.
Maturity
GAGenerally available in the API and apps. The weights aren't out yet; Moonshot has committed to releasing them by Nov 4.
How to track it
- Weights: check whether K3.1 Pro weights and a license appear under the moonshotai org on Hugging Face by Nov 4.
- Independent numbers: look for K3.1 Pro on Artificial Analysis and the official Terminal-Bench leaderboard.
- Pricing: watch the Kimi API pricing page for Highspeed rates and cache pricing changes.