Claude Sonnet 5.5 API

Claude Sonnet 5.5 is a large language model by Anthropic, available on the Venice API as claude-sonnet-5-5. Requests are anonymized, so the provider never sees your identity.Claude Sonnet 5.5 is a step-change improvement over Sonnet 5. It performs great with well-scoped everyday tasks like building features, fixing bugs, and creating polished documents, slides, and spreadsheets. Sonnet 5.5 also improves on communication and writes more clearly than Sonnet 5. It features a 1M token context window, 128K max output tokens, adaptive thinking, and strong document and vision understanding.

Claude Sonnet 5.5 API pricing

Model ID	Variant	Privacy	Price
`claude-sonnet-5-5`	Standard	Anonymized	$3.75 input /$ 18.75 output per 1M tokens

Claude Sonnet 5.5 specifications

Spec	Value
Provider	Anthropic
Released	Sep 26, 2026
Privacy	Anonymized
Context window	1M tokens
Max output	125K tokens
Reasoning effort	low, medium, high, xhigh, max

How to use the Claude Sonnet 5.5 API

Send requests to POST https://api.venice.ai/api/v1/chat/completions with "model": "claude-sonnet-5-5" and your API key.

curl https://api.venice.ai/api/v1/chat/completions \
  -H "Authorization: Bearer $VENICE_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "claude-sonnet-5-5",
    "messages": [{ "role": "user", "content": "Explain TEE attestation in two sentences." }],
    "reasoning_effort": "medium"
  }'

Claude Sonnet 5.5 API FAQ

How much does the Claude Sonnet 5.5 API cost?

3.75 per 1M input tokens and

18.75 per 1M output tokens, with cached input at $0.38 per 1M. Prices are in USD and can be paid in DIEM at parity.

What is the Claude Sonnet 5.5 model ID?

Use claude-sonnet-5-5 as the model parameter.

Is the Claude Sonnet 5.5 API private?

Claude Sonnet 5.5 is anonymized: Venice forwards requests to the provider without your identity, but the provider may retain prompt data, so use a private model for sensitive work.

What is the context window of Claude Sonnet 5.5?

1M tokens of context, with up to 125K output tokens per response.

What does Claude Sonnet 5.5 support?

Claude Sonnet 5.5 supports function calling, structured outputs, reasoning, image input, web search and prompt caching. Reasoning effort is adjustable with reasoning_effort: low, medium, high, xhigh and max (default medium).

Which endpoint does the Claude Sonnet 5.5 API use?

Call POST /chat/completions. /responses (Alpha) is also supported.

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