Long documents in one go
Paste reports, contracts or code files. Each message can carry about 128K tokens, and the model itself reads up to 1M.
Moonshot AI · Kimi K3.1 Pro · 1M context
Chat with Kimi K3.1 Pro
Kimi K3.1 Pro is Moonshot AI’s newest open-weight model, with a 1M-token context window and strong coding, research and vision skills. Chat with it here in your browser: send text, images or a short video, and pay only for what each message uses.
- 1Mtoken context window
- 2speeds: Pro and Highspeed
- 1credit minimum per message
What can Kimi K3.1 Pro do for you?
Code, research, long documents, images and video. Ask anything.
THE MODEL
What is Kimi K3.1 Pro?
Kimi K3.1 Pro is the first model in Moonshot AI’s K3.1 series, released on October 23, 2026. It is a post-trained version of Kimi K3 with much more reinforcement learning, aimed at coding, 3D and design work, financial research and agent tasks.
Moonshot reports 65.7% on Terminal-Bench 4.0, ahead of GPT-6 Astra (58.2%) and just behind Claude Opus 5.5 (66.4%), and a much lower hallucination rate than K3 on its internal stress test. These are Moonshot’s own numbers.
- Developer
- Moonshot AI
- Released
- October 23, 2026
- Context window
- 1,048,576 tokens (this site: about 128K per message)
- Input
- Text, images, video
- Output
- Text, with visible reasoning
- Weights
- Open weights promised by November 4, 2026
Sources: Moonshot AI’s announcement and the public OpenRouter model listing, checked October 27, 2026.
FEATURES
Everything Kimi K3.1 Pro can do, in one chat
Images and short videos
Attach screenshots, photos, charts or a short clip and ask about them. Files are used for that message only and are not stored.
Built for coding
Moonshot reports 65.7% on Terminal-Bench 4.0. Replies render Markdown with fenced code blocks you can copy.
Pro or Highspeed
Switch to Highspeed when you want answers 2–3× faster. It costs twice as much per token.
Reasoning you can read
Kimi thinks before it answers. The reasoning streams into a collapsible panel above the reply.
Pay for what you use
Billed by tokens, from 1 credit per message. Unused credits held for a reply come back as soon as it finishes.
HOW IT WORKS
Three steps to an answer
- 1
Write or attach
Type a question, paste a long text, or attach images or a short video.
- 2
Pick a speed
K3.1 Pro by default, or Highspeed for faster replies.
- 3
Read and follow up
Watch the reasoning and answer stream in, then keep the thread going.
PRICING
From 1 credit per message
Every message is billed by the tokens it uses, rounded up to whole credits, with a minimum of 1 credit. A short question and answer usually costs 1 to 3 credits.
ModelInputOutputCached input
K3.1 Pro512536
Highspeed1025066
Credits per 1M tokens. Reasoning tokens count as output.
FAQ
Kimi K3.1 Pro questions
What is Kimi K3.1 Pro?
Kimi K3.1 Pro is an 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, built for coding, research and agent work. Moonshot says the full weights will be released by November 4, 2026.
Is this the official Kimi website?
No. Kimi K3.1 Pro Online (kimi-k31.com) is an independent site. It is not affiliated with or endorsed by Moonshot AI. It sends your messages to Kimi K3.1 Pro through a hosted model API. The official Kimi app is at kimi.ai.
How much does a message cost?
Messages are billed by the tokens they use, with a minimum of 1 credit. On K3.1 Pro that is 51 credits per million input tokens and 253 per million output tokens; Highspeed costs twice as much. A short question and answer usually costs 1 to 3 credits.
Is Kimi K3.1 Pro free here?
You can claim free credits through the daily check-in when it is offered, and those credits work like purchased ones. After that you pay per message with a credit plan or a one-time pack.
Can I send images or video?
Yes. Attach up to 4 images (5 MB each) or one short video (16 MB) to a message. They are sent to the model with that message only and are not stored by this site.
What is the difference between Pro and Highspeed?
Both run the same Kimi K3.1 Pro model. Moonshot says Highspeed answers 2 to 3 times faster; it costs twice as much per token here.
How long can my messages be?
Kimi K3.1 Pro supports a 1M-token context, but this site caps each message, including the earlier turns sent as context, at about 128K tokens to keep costs predictable. Very long chats keep the most recent turns.
Are my chats private?
Chats are stored in your account and you can delete them. To generate replies, your messages are sent through OpenRouter to Moonshot AI. Do not share passwords, secrets or sensitive personal data.
An independent site
Kimi K3.1 Pro Online is not affiliated with or endorsed by Moonshot AI. Kimi is a trademark of its owner. We send your messages to Kimi K3.1 Pro through OpenRouter and bill for usage with our own credits.
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