Kimi K3.1 Pro Online

Guide · Kimi K3.1 Pro

What is Kimi K3.1 Pro?

Kimi K3.1 Pro is a large open-weight AI model from Moonshot AI, released on October 23, 2026. It is a post-trained version of Kimi K3 with a 1M-token context window, image and video input, and a focus on coding, research and agent work. Moonshot says the full weights will be released by November 4, 2026.

Chat with Kimi K3.1 Pro

In short

  • Released by Moonshot AI on October 23, 2026, as the first model in the K3.1 series.
  • Context window of 1,048,576 tokens; reads text, images and video and writes text.
  • A mixture-of-experts model with about 2.8T total and 104B active parameters, according to ArtificialWatch.
  • API list price: $2 per 1M input tokens and $10 per 1M output tokens; Highspeed is $4 and $20.
  • Moonshot reports 65.7% on Terminal-Bench 4.0; benchmark figures are Moonshot's own runs.

Where it comes from

Moonshot AI describes Kimi K3.1 Pro as a post-trained version of Kimi K3, trained with substantially more reinforcement learning across hundreds of task domains. It launched together with Kimi K3.1 Pro Highspeed, which Moonshot says runs 2 to 3 times faster.

At launch it was available in the Kimi apps, Kimi Work, Kimi Code and the Kimi API, and on OpenRouter as moonshotai/kimi-k3.1-pro.

What it is good at

Moonshot's announcement highlights four areas. The numbers below are Moonshot's own evaluations, not independent results.

  • Coding: 65.7% on Terminal-Bench 4.0, ahead of GPT-6 Astra (58.2%) and just behind Claude Opus 5.5 (66.4%).
  • 3D and design: 92.7% on BenchCAD with tools, with Blender and CAD scripting.
  • Finance and research: 64.4 on OfficeQA Pro v2, which Moonshot calls state of the art.
  • Factual accuracy: the claim-level hallucination rate on Moonshot's internal stress test fell from 23.4% for K3 to 8.3%.

How to try it

You can use Kimi K3.1 Pro in the official Kimi apps, through the Kimi or OpenRouter APIs, or in an independent web chat such as this one.

  1. Open the chat. Sign in on kimi-k31.com and type a question, paste a long document, or attach images or a short video.
  2. Pick a speed. K3.1 Pro by default, or Highspeed when you want faster answers at twice the token price.
  3. Read and follow up. The reasoning streams first, then the answer; follow up in the same thread.

Frequently asked questions

Who makes Kimi K3.1 Pro?

Moonshot AI, the Beijing-based company behind the Kimi assistant. It released Kimi K3.1 Pro on October 23, 2026.

How big is the Kimi K3.1 Pro context window?

1,048,576 tokens, about 1M. This site caps each message, including earlier turns sent as context, at about 128K tokens to keep costs predictable.

Can Kimi K3.1 Pro understand images and video?

Yes. It accepts image and video input along with text. On this site you can attach up to 4 images or one short video per message.

Is kimi-k31.com the official Kimi website?

No. Kimi K3.1 Pro Online is an independent site that sends your messages to Kimi K3.1 Pro through OpenRouter. It is not affiliated with or endorsed by Moonshot AI. The official Kimi apps are at kimi.ai.

Sources

Updated 2026-10-27. Kimi K3.1 Pro Online is an independent site and is not affiliated with or endorsed by Moonshot AI. Kimi is a trademark of its owner. Model replies can be wrong; check important facts and code.