openapi: 3.1.0
info:
  title: OpenRouter Chat Generation API
  description: OpenRouter provides unified access to hundreds of AI models through a single API endpoint. It implements the OpenAI API specification for chat completions, allowing developers to use any model with the same request and response format. The API also exposes model discovery, generation statistics, credits and balance information, and provisioning endpoints for programmatic key management.
  version: '1.0'
  contact:
    name: OpenRouter
    url: https://openrouter.ai/
  license:
    name: Proprietary
    url: https://openrouter.ai/terms
servers:
- url: https://openrouter.ai/api/v1
  description: OpenRouter production API
security:
- BearerAuth: []
tags:
- name: Generation
  description: Query stats and usage for completed generations.
paths:
  /generation:
    get:
      operationId: getGeneration
      summary: Get generation stats
      description: Retrieves usage statistics for a completed generation including token counts, cost, cached tokens, and reasoning tokens.
      tags:
      - Generation
      parameters:
      - name: id
        in: query
        required: true
        schema:
          type: string
        description: Generation identifier returned in chat completion responses.
      responses:
        '200':
          description: Generation statistics.
          content:
            application/json:
              schema:
                type: object
components:
  securitySchemes:
    BearerAuth:
      type: http
      scheme: bearer
      bearerFormat: OPENROUTER_API_KEY
externalDocs:
  description: OpenRouter API Reference
  url: https://openrouter.ai/docs/api/reference/overview