Claude Sonnet 4.6 API — pricing & specs

Claude Sonnet 4.6, made by Anthropic, accepts text and image input and returns text. On KeepRouter, Claude Sonnet 4.6 costs $3.00 per 1M input tokens and $15.00 per 1M output tokens, billed pay-as-you-go with no monthly fee. Call it through a compatible KeepRouter endpoint supported by its active route, with the model id claude-sonnet-4-6.

MakerAnthropic
ModalityText, vision
Input price$3.00 per 1M tokens
Output price$15.00 per 1M tokens
Cached input$0.3000 per 1M tokens
CapabilitiesVision (image input), Chat completions, Streaming where supported, Tool calling where supported
EndpointPOST /v1/chat/completions or POST /v1/messages (compatible chat routes)
Model idclaude-sonnet-4-6

How pricing works for Claude Sonnet 4.6

Claude Sonnet 4.6 is billed per token — $3.00 per 1M input tokens and $15.00 per 1M output tokens, with cached input at $0.3000 per 1M tokens. The published price is pay-as-you-go, with no monthly fee; actual request cost depends on measured token usage.

Calling Claude Sonnet 4.6 on KeepRouter

Point a compatible client at the supported KeepRouter endpoint and set the model to claude-sonnet-4-6. KeepRouter preserves the client-facing request shape while handling upstream routing or translation. Use POST /v1/chat/completions or, on compatible chat routes, POST /v1/messages; streaming and tool support depend on the model's active route.

cURL

curl https://keeprouter.com/v1/chat/completions \
  -H "Authorization: Bearer $KEEPROUTER_KEY" -H "Content-Type: application/json" \
  -d '{"model":"claude-sonnet-4-6","messages":[{"role":"user","content":"Hello"}]}'

Python

from openai import OpenAI
client = OpenAI(base_url="https://keeprouter.com/v1", api_key="$KEEPROUTER_KEY")
r = client.chat.completions.create(model="claude-sonnet-4-6", messages=[{"role":"user","content":"Hello"}])

JavaScript

import OpenAI from "openai";
const client = new OpenAI({ baseURL: "https://keeprouter.com/v1", apiKey: process.env.KEEPROUTER_KEY });
const r = await client.chat.completions.create({ model: "claude-sonnet-4-6", messages: [{ role: "user", content: "Hello" }] });

Source and verification boundary

Official Anthropic website. KeepRouter's live catalog is authoritative for the customer price and enabled endpoint shown here; the maker remains authoritative for upstream model capabilities and limits.

Guides

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Catalog facts and prices last changed 2026-08-01.