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POST/v1/messages

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POST/v1/messages
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Requests use the API key you enter and follow standard API billing.

Claude Sonnet 5.5

Request ID claude-sonnet-5-5

Protocols

Authentication

Requests require an API key from API key management. For JSON requests, set Content-Type: application/json.

  • Anthropic Messages · x-api-key: YOUR_API_KEY

Request parameters

POST /v1/messages

FieldTypeRequiredDescription
modelstringRequiredSet the model ID to claude-sonnet-5-5.
messagesobject[]RequiredSend user and assistant messages in order. Put system instructions in the top-level system field.
messages[].contentstring / object[]RequiredThe message body. Use plain text or an array of content blocks defined by the protocol.
messages[].content[]objectConditionalUse a type: image content block and put image data in source. Accepted formats depend on the endpoint.
systemstring / object[]OptionalSystem instructions as text or an array of text blocks.
max_tokensintegerRequiredCaps output tokens. The accepted limit depends on the model and endpoint.
streambooleanOptionaltrue requests an SSE stream. false requests a JSON response. Available modes depend on the endpoint.
thinking.typestringOptionalUse adaptive or between_tools. The latter limits reasoning to the intervals between tool calls.
output_config.effortstringConditionalRequested reasoning effort. Available levels and whether reasoning can be disabled depend on the model and endpoint.
toolsobject[]ConditionalTool definitions available to the model. Tool types and parameter formats depend on the protocol and endpoint.
tool_choiceobjectConditionalUse type: auto for ordinary tools. This model does not support forcing ordinary tool calls with any or tool.

POST /v1/messages/count_tokens

FieldTypeRequiredDescription
modelstringRequiredSet the model ID to claude-sonnet-5-5.
messagesobject[]RequiredSend user and assistant messages in order. Put system instructions in the top-level system field.
messages[].contentstring / object[]RequiredThe message body. Use plain text or an array of content blocks defined by the protocol.
messages[].content[]objectConditionalUse a type: image content block and put image data in source. Accepted formats depend on the endpoint.
systemstring / object[]OptionalSystem instructions as text or an array of text blocks.
toolsobject[]ConditionalTool definitions to include in the input token count. Send the same tools as in the Messages request.

Request examples

Set your API key in the local ICODEEASY_API_KEY environment variable and choose an endpoint that accepts direct HTTP calls. For endpoints that require a specific client, follow that client’s setup guide.

Anthropic Messages

bash
curl -sS 'https://api.icodeeasy.cc/v1/messages' \
  -H "x-api-key: $ICODEEASY_API_KEY" \
  -H 'Content-Type: application/json' \
  -H 'anthropic-version: 2023-06-01' \
  --data '{
  "model": "claude-sonnet-5-5",
  "max_tokens": 256,
  "messages": [
    {
      "role": "user",
      "content": "Explain how a rainbow forms in one sentence."
    }
  ]
}'

Count Tokens

bash
curl -sS 'https://api.icodeeasy.cc/v1/messages/count_tokens' \
  -H "x-api-key: $ICODEEASY_API_KEY" \
  -H 'Content-Type: application/json' \
  -H 'anthropic-version: 2023-06-01' \
  --data '{
  "model": "claude-sonnet-5-5",
  "messages": [
    {
      "role": "user",
      "content": "Explain how a rainbow forms in one sentence."
    }
  ]
}'

Read the response

  • Anthropic Messages · Read blocks of type text in content[]. In a stream, process SSE content block events in order. JSON · SSE
  • Count Tokens · Read the input token count from input_tokens.

Full integration guide

Capabilities and limits

  • streaming · Supported
  • tool_calling · Supported
  • image_input · Conditional — Depends on the compatible endpoint and request format
  • video_input · Not supported

Compatibility aliases and retired redirects

  • claude-sonnet-4-5, claude-sonnet-4-5-20250514, claude-sonnet-4-5-20250929, claude-sonnet-4-6 → claude-sonnet-5-5 (Retired redirect)

Model Capability Catalog · View pricing

Related guides

Install Claude Code, Configure a Custom API, and Troubleshoot Windows

Install Claude Code, configure a custom API key and URL, verify Windows or Unix settings, and troubleshoot authentication, rate limits, and connections.

Anthropic Messages

Send a request in the Anthropic Messages format. This page covers direct HTTP calls, with Claude Code setup covered in the related guides.

Model Capability Catalog

Compare public text, image, and video models by normalized request ID, compatible protocols, supported clients, tool use, media capabilities, limits, and review date.

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