> ## Documentation Index
> Fetch the complete documentation index at: https://docs.aireserve.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Create message

> Anthropic-compatible Messages endpoint. Claude Code, the Claude Agent SDK, and the Anthropic SDK connect here — and every gateway model answers, not just Claude.



## OpenAPI

````yaml /api-reference/openapi.json post /v1/messages
openapi: 3.0.3
info:
  title: AI Reserve Gateway API
  description: >-
    The AI Reserve AI gateway REST surface — OpenAI-compatible chat completions,
    Anthropic-compatible messages, Bedrock Converse, images, video, and files
    behind one endpoint and one API key.
  version: 1.0.0
servers:
  - url: https://api.aireserve.com
security:
  - bearerAuth: []
paths:
  /v1/messages:
    post:
      tags:
        - Messages
      summary: Create message
      description: >-
        Anthropic-compatible Messages endpoint. Claude Code, the Claude Agent
        SDK, and the Anthropic SDK connect here — and every gateway model
        answers, not just Claude.
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              additionalProperties: true
            example:
              model: claude-sonnet-4-6
              max_tokens: 256
              messages:
                - role: user
                  content: Hello!
      responses:
        '200':
          description: Default Response
components:
  securitySchemes:
    bearerAuth:
      type: http
      scheme: bearer
      description: >-
        Your AI Reserve API key (aireserve_api_…) from Profile → My API Keys in
        the portal.

````