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Anthropic

claude-sonnet-4-6 API

Claude Sonnet 4.6 is a legacy Sonnet model supporting adaptive reasoning for long-document and application workflows.

MODALITIES
TextText
Available
INPUT / OUTPUT70% OFF
$0.9/ 1M
/
$4.5/ 1M
USD per million tokens
CACHED INPUT
$0.09/ 1M
Platform price · USD
CONTEXT WINDOW
128,000tokens
Max output: 64,000 tokens
Input
Sign in to choose a key from your account.
Choose a level supported by this model. Default keeps the model’s own settings; thinking also consumes output tokens.
Advanced request options are available in JSON mode.
Request preview
{
  "model": "claude-sonnet-4-6",
  "max_tokens": 1024,
  "messages": [
    {
      "role": "user",
      "content": "A quiet mountain lake at sunrise, soft morning light."
    }
  ],
  "stream": true
}
Output

Your next idea starts here.

Run the model to preview your result.

API Usage Examples

API documentation ↗
POSTGet API Key ↗
curl 'https://newrouters.com/v1/messages' \
  -H "Content-Type: application/json" \
  -H "x-api-key: $MODEL_API_KEY" \
  -H "anthropic-version: 2023-06-01" \
  --data '{
  "model": "claude-sonnet-4-6",
  "max_tokens": 1024,
  "messages": [
    {
      "role": "user",
      "content": "Explain how an HTTP request works in three concise steps."
    }
  ],
  "stream": false
}'

Set MODEL_API_KEY in your server environment. Requests use this model’s native API and your account pricing.

Docs: authentication and keys · Error handling

claude-sonnet-4-6 pricing

Estimate one request, then choose a budget for your workflow.

UsageQuantityRateCost
tokens$0.9/ 1M$0.0009
tokens$0.09/ 1M$0
tokens$1.125/ 1M$0
tokens$1.8/ 1M$0
tokens$4.5/ 1M$0.00225
tokens$4.5/ 1M$0
Cost per request$0.00315

Public USD estimate. Your account rate and final recorded usage determine the actual charge.

Model pricing details
SpecificationOur priceOfficial reference
Input$0.9 / 1M tokens$3 About 70% less than official
Cached input$0.09 / 1M tokens$0.3 About 70% less than official
Cache write · 5m$1.125 / 1M tokens$3.75 About 70% less than official
Cache write · 1h$1.8 / 1M tokens$6 About 70% less than official
Output$4.5 / 1M tokens$15 About 70% less than official
Reasoning$4.5 / 1M tokens$15 About 70% less than official

claude-sonnet-4-6 API · Examples

Original prompts adapted to documented capabilities; these are not vendor-generated outputs.

Official source ↗ · 2026-10-14

EXAMPLE PROMPT

Synthesize these documents into a decision timeline, contradictions and open tasks. Reference the source paragraph for each conclusion. Documents: [paste material]

USER MESSAGE
01

Long-document synthesis

Preserve source references, contradictions and open questions instead of a generic summary.

EXAMPLE PROMPT

Find boundary errors in this TypeScript function. Provide a minimal fix and tests for nulls, repeated calls and errors. Code: [paste code]

USER MESSAGE
02

Code repair

Validate a minimal code change against explicit boundary cases.

What Is claude-sonnet-4-6?

Claude Sonnet 4.6 is a legacy Sonnet model supporting adaptive reasoning for long-document and application workflows.

Official model information ↗ · 2026-10-14

claude-sonnet-4-6 Platform specifications

Specificationclaude-sonnet-4-6
Model IDclaude-sonnet-4-6
ProviderAnthropic
API/v1/messages
Context window128,000 tokens
Maximum output64,000 tokens
Declared capabilitiesTools · Streaming · Reasoning · Structured output
Protocol & capability details

Protocol & capabilities

claude · claude-sonnet-4-6

Context limit
128000
Maximum output
64000

tools · stream · reasoning · structured_output

Compare claude-sonnet-4-6 with related models

Specificationclaude-sonnet-4-6Claude Fable 5Claude Fable 5.1
ProviderAnthropicAnthropicAnthropic
Input → outputTextTextTextTextTextText
Selection basisCurrent modelSame claude protocol · Same billing unitsSame claude protocol · Same billing units
Context / max output128,000 / 64,0001,000,000 / 128,0001,000,000 / 128,000
Starting price$0.9 / 1M tokens$3 / 1M tokens$3 / 1M tokens

Choose by the input types, output settings and billing unit your workflow needs. Try the same prompt across models to compare results for your own use case.

Integrate claude-sonnet-4-6 into your app

Keep the native request format and point your application to the platform API. Prepare a key with model access, then review status and charges in your usage records.

View API examples

claude-sonnet-4-6 API · Common Questions

Everything you need to know about API access, pricing and model capabilities.

How is claude-sonnet-4-6 billed?

Charges depend on the recorded token usage and your account rates. Input, output and supported cache or reasoning categories are listed separately in the pricing table. The calculator uses public USD prices; the final usage receipt determines the charge.

How do I get an API key?

Choose “Get API access” to open the integration guide. Sign in to your NewRouters account, prepare a key with access to this model and copy an API example.

Which API endpoints can I use?

Supported endpoints: /v1/messages、/v1/messages/count_tokens. Choose an endpoint in the API examples to see its native request format.

Does the model support streaming?

The current model route declares streaming support. Use the native endpoint’s streaming option and consume its events. Usage already completed may still be billed if the connection is interrupted.

Can I use tools or structured output?

Tools: supported. Structured output: supported. Request fields follow the selected native endpoint.

Where can I check usage and charges?

Keep the request ID and open your account’s LLM usage records to inspect request status, token counts and charges. Prompt and answer content are not a conversation history in this view.

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Integration topics / Documentation

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