Grok 4 · fastrouter

Grok 4, launched by xAI in July 2025, represents a significant leap in large language model development. Building on earlier versions like Grok 3 and the original 2023–24 models, Grok 4 introduces several key enhancements aimed at performance, versatility, and real-world application. It features an extended context window of up to 256,000 tokens, enabling it to process long documents, codebases, or conversations with greater depth and continuity. The model demonstrates strong performance in advanced reasoning tasks, including mathematics and programming. Its architecture supports multimodal input, with capabilities for vision and voice currently in development, and introduces advanced voice interaction with faster response times and more natural flow.

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

Input, $/1M $3.00

Output, $/1M $15.00

Cache read $0.75

Cache write $15.00

Context 256 000

Max output 64 000

Accepts text

Last checked 04.11.2026 12:26:37 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	`x-ai/grok-4`

curl

curl https://go.fastrouter.ai/api/v1/chat/completions \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model": "x-ai/grok-4", "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": "x-ai/grok-4",
      "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": "x-ai/grok-4",
    "messages": [
      {
        "role": "user",
        "content": "Hello!"
      }
    ],
    "max_tokens": 256
  }),
});
console.log(await r.json());

Request (JSON)

{
  "model": "x-ai/grok-4",
  "messages": [
    {
      "role": "user",
      "content": "Hello!"
    }
  ],
  "max_tokens": 256
}

Response (JSON)

{
  "id": "chatcmpl-...",
  "object": "chat.completion",
  "model": "x-ai/grok-4",
  "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%7Cx-ai/grok-4, prices checked 2026-11-04; seller's page: https://fastrouter.ai

Technical details

ID: offer:fastrouter|x-ai/grok-4