MoonshotAI: Kimi K3.1 Pro · fastrouter

Kimi K3.1 Pro is Moonshot AI's flagship open-weight multimodal reasoning model and the first in the K3.1 series, a post-trained version of Kimi K3 with substantially more post-training compute, built on the same Kimi Delta Attention and Attention Residuals architecture (K3: 2.8T total, 104B active parameters; Moonshot calls K3.1 Pro 3T-class). It has a 1M-token context window with flat pricing across the full window, accepts text and images, and returns text, with always-on reasoning (effort: low, high, or max; default max) that cannot be turned off. It is designed for long-horizon coding, agentic and tool-using workflows, and complex knowledge work, and is exposed through an OpenAI-compatible chat completions API. Moonshot has said full weights will be released by November 4, 2026.

Base model All models on this base All models of the provider to the provider

Input, $/1M $2.00

Output, $/1M $10.00

Cache read $0.20

Cache write —

Context 1 048 576

Max output 1 048 576

Accepts images, text

Last checked 04.11.2026 12:00:14 UTC

Source provider's page

Price alerts

API

OpenAI-compatible API: the official OpenAI SDKs work with this base URL. Replace YOUR_API_KEY with your key from the provider.

API base URL	`https://go.fastrouter.ai/api/v1`
Endpoint	`https://go.fastrouter.ai/api/v1/chat/completions`
Model id	`moonshotai/kimi-k3.1-pro`

curl

curl https://go.fastrouter.ai/api/v1/chat/completions \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model": "moonshotai/kimi-k3.1-pro", "messages": [{"role": "user", "content": "Hello!"}], "max_tokens": 256}'

Python

import requests

r = requests.post(
    "https://go.fastrouter.ai/api/v1/chat/completions",
    headers={"Authorization": "Bearer YOUR_API_KEY"},
    json={
      "model": "moonshotai/kimi-k3.1-pro",
      "messages": [
        {
          "role": "user",
          "content": "Hello!"
        }
      ],
      "max_tokens": 256
    },
)
print(r.json())

JavaScript

const r = await fetch("https://go.fastrouter.ai/api/v1/chat/completions", {
  method: "POST",
  headers: {Authorization: "Bearer YOUR_API_KEY", "Content-Type": "application/json"},
  body: JSON.stringify({
    "model": "moonshotai/kimi-k3.1-pro",
    "messages": [
      {
        "role": "user",
        "content": "Hello!"
      }
    ],
    "max_tokens": 256
  }),
});
console.log(await r.json());

Request (JSON)

{
  "model": "moonshotai/kimi-k3.1-pro",
  "messages": [
    {
      "role": "user",
      "content": "Hello!"
    }
  ],
  "max_tokens": 256
}

Response (JSON)

{
  "id": "chatcmpl-...",
  "object": "chat.completion",
  "model": "moonshotai/kimi-k3.1-pro",
  "choices": [
    {
      "index": 0,
      "message": {
        "role": "assistant",
        "content": "Hi! How can I help?"
      },
      "finish_reason": "stop"
    }
  ],
  "usage": {
    "prompt_tokens": 9,
    "completion_tokens": 12,
    "total_tokens": 21
  }
}

The address is taken from the provider's model list; check it against the provider's documentation.

Provider's API documentation

Source: AI Rate Card, https://airatecard.com/en/c/offer%3Afastrouter%7Cmoonshotai/kimi-k3.1-pro, prices checked 2026-11-04; seller's page: https://fastrouter.ai

Technical details

ID: offer:fastrouter|moonshotai/kimi-k3.1-pro