# claude-sonnet-4-6 — API, pricing & specs via nRouter

> claude-sonnet-4-6 is available through nRouter, the managed LLM gateway: one OpenAI-compatible API key, 0% token markup (exact provider list pricing), 0% platform fee, built-in guardrails, and per-request cost tracking.

## What it is

Claude Sonnet 4.6 provides balanced speed and intelligence with a 1M token context window, designed for enterprise software engineering and agentic planning.

Source: https://platform.claude.com/docs/en/models/sonnet-4-6/overview

## Facts

- Maker: Anthropic
- Released: 2026-02-17
- Context window: 1,000,000 tokens
- Max output: 128,000 tokens
- Served on: Anthropic

## nRouter list pricing (exact provider rates, 0% markup)

- Input: $3 per 1M tokens
- Output: $15 per 1M tokens

Settled at the exact provider list price above. nRouter adds no per-token markup and charges a 0% platform fee (see https://nrouter.ai/pricing).

## Use it

```python
from openai import OpenAI

client = OpenAI(
    base_url="https://api.nrouter.ai/v1",
    api_key="sk-nrouter-YOUR_KEY",  # create one at https://nrouter.ai/signup
)

response = client.chat.completions.create(
    model="anthropic/claude-sonnet-4-6",
    messages=[{"role": "user", "content": "Hello"}],
)
```

Model page: https://nrouter.ai/models/claude-sonnet-4-6
Full nRouter index for AI engines: https://nrouter.ai/llms.txt
Docs: https://nrouter.ai/docs