Claude Sonnet 5.5

Anthropic's production-standard Sonnet model for coding, agents, and long-context enterprise workloads.

Flagship Sonnet1M Context$2/$10 Permanent

Context Window

1M tokens

claude-sonnet-5-5

Max Output

1M tokens

Input

$1.8$2.00

10% off

1M tokens

Output

$9$10.00

10% off

1M tokens

Model Codeclaude-sonnet-5-5

Playground

Model Code

claude-sonnet-5-5

Enter your prompt here...

Output

No output yet

Pricing

Plan	Context Window	Max Output	Input	Output	Cache Write	Cache Read
claude-sonnet-5-5	1M tokens	-	$1.8$2.0010% off 1M tokens	$9$10.0010% off 1M tokens	$2.25$2.5010% off 1M tokens	$0.18$0.2010% off 1M tokens

Official Anthropic list pricing. All prices are per 1M tokens.

Prompt cache reads are billed at 10% of the input rate, and cache writes at 1.25× the input rate.

Cache read or cached input pricing applies to reused prompt tokens.

README

Claude Sonnet 5.5 is Anthropic's production-standard Sonnet-tier model, pairing strong coding, reasoning, and long-context performance with a 1M-token context window and the permanent $2/$10 rate.

Claude Sonnet 5.5 carries the Sonnet line's production standard with a 1M-token context window, strong coding and long-context reasoning, and the permanent $2/$10 price.
Prompt caching reads at 10% of input (up to 90% savings), cache writes at 1.25× input, and the Batch API offers 50% off for eligible workloads.
ReachAPI exposes the model through the `claude-sonnet-5-5` model code over the Claude Messages protocol.

API

Use the API docs for request format, parameters, and integration details.

Anthropic's production-standard Sonnet model for coding, agents, and long-context enterprise workloads.

Model Code

claude-sonnet-5-5

View API Docs

API

Endpoint

POST /v1/messages

Authentication

Authorization: Bearer YOUR_REACH_API_KEY
anthropic-version: 2023-06-01
Content-Type: application/json

Example

curl -X POST "https://direct.reachapi.ai/v1/messages" \
  -H "Authorization: Bearer YOUR_REACH_API_KEY" \
  -H "anthropic-version: 2023-06-01" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "YOUR_MODEL_ID",
    "messages": [
      {
        "role": "user",
        "content": "Introduce ReachAPI in one sentence."
      }
    ],
    "max_tokens": 512,
    "temperature": 0.2
  }'

Related Models

Other models from the same vendor

Claude Haiku 5.5

Anthropic's fastest, most cost-efficient model for low-latency assistants and high-volume automation.

Claude Opus 5.5

Anthropic's flagship model for deep reasoning, complex agentic coding, and long-horizon enterprise work.

Claude Fable 5

Anthropic's most capable widely released model for next-generation intelligence and long-running agents.

Claude Opus 5

Anthropic's flagship model for deep reasoning, complex agentic coding, and long-horizon enterprise work.

Claude Sonnet 5

Anthropic's new Sonnet model for extended-context coding, agents, and enterprise production workflows.

Claude Opus 4.8

Anthropic's newest Opus-tier model for complex reasoning, long-horizon agentic coding, and high-autonomy enterprise work.