OpenRouter Completions API

openapi: 3.1.0
info:
  title: OpenRouter Chat Completions 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: Completions
  description: Legacy completions endpoint.
paths:
  /completions:
    post:
      operationId: createCompletion
      summary: Create completion
      description: Legacy text completion endpoint that takes a prompt and returns a completion.
      tags:
      - Completions
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/CompletionRequest'
      responses:
        '200':
          description: Completion response.
          content:
            application/json:
              schema:
                type: object
components:
  schemas:
    CompletionRequest:
      type: object
      required:
      - model
      - prompt
      properties:
        model:
          type: string
        prompt:
          type: string
        max_tokens:
          type: integer
        temperature:
          type: number
        stream:
          type: boolean
  securitySchemes:
    BearerAuth:
      type: http
      scheme: bearer
      bearerFormat: OPENROUTER_API_KEY
externalDocs:
  description: OpenRouter API Reference
  url: https://openrouter.ai/docs/api/reference/overview