Anthropic: Claude Opus 4.1 · fastrouter

Claude Opus 4.1, a direct replacement for Opus 4, excels in real-world coding and agentic tasks with enhanced performance and precision. It autonomously handles complex, end-to-end development tasks, adapting to user styles while maintaining high-quality output, particularly in frontend code generation and intricate logic. With superior long-horizon task management and problem-solving, it serves as an ideal virtual collaborator for sustained reasoning and multi-step actions. Opus 4.1 also boosts AI agent capabilities, enabling accurate execution of complex tasks and shining in agentic search, research, content creation, and context management for comprehensive insights and high-quality summarization.

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

Input, $/1M $15.00

Output, $/1M $75.00

Cache read $1.50

Cache write —

Context 200 000

Max output 32 000

Accepts files, 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	`anthropic/claude-opus-4.1`

curl

curl https://go.fastrouter.ai/api/v1/chat/completions \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model": "anthropic/claude-opus-4.1", "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": "anthropic/claude-opus-4.1",
      "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": "anthropic/claude-opus-4.1",
    "messages": [
      {
        "role": "user",
        "content": "Hello!"
      }
    ],
    "max_tokens": 256
  }),
});
console.log(await r.json());

Request (JSON)

{
  "model": "anthropic/claude-opus-4.1",
  "messages": [
    {
      "role": "user",
      "content": "Hello!"
    }
  ],
  "max_tokens": 256
}

Response (JSON)

{
  "id": "chatcmpl-...",
  "object": "chat.completion",
  "model": "anthropic/claude-opus-4.1",
  "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%7Canthropic/claude-opus-4.1, prices checked 2026-11-04; seller's page: https://fastrouter.ai/models/anthropic/claude-opus-4.1

Technical details

ID: offer:fastrouter|anthropic/claude-opus-4.1