openapi: 3.0.1
info:
  title: LangDB AI Gateway Analytics Models API
  description: OpenAI-compatible REST API for the LangDB AI Gateway. A single, project-scoped endpoint routes chat completions, embeddings, and image generation across 250+ models from providers such as OpenAI, Anthropic, Google, Meta, Mistral, and DeepSeek, while adding routing, guardrails, tracing, cost control, and an MCP (Model Context Protocol) gateway. Requests are authenticated with a Bearer API key and scoped to a project either by embedding the project id in the path (`/{project_id}/v1/...`) or by sending an `X-Project-Id` header. Tracing and session headers (`X-Thread-Id`, `X-Run-Id`, `X-Label`) attach observability metadata to each call.
  termsOfService: https://langdb.ai/terms
  contact:
    name: LangDB Support
    url: https://langdb.ai
    email: support@langdb.ai
  version: '1.0'
servers:
- url: https://api.us-east-1.langdb.ai/{project_id}/v1
  description: Project-scoped OpenAI-compatible base (US East 1).
  variables:
    project_id:
      default: your-langdb-project-id
      description: LangDB project id. May instead be supplied via the X-Project-Id header.
- url: https://api.us-east-1.langdb.ai
  description: Root base URL for analytics, usage, and thread management endpoints (US East 1).
security:
- bearerAuth: []
tags:
- name: Models
  description: Catalog of models available through the gateway.
paths:
  /models:
    get:
      operationId: listModels
      tags:
      - Models
      summary: List models
      description: Lists the models available to the project through the gateway, in an OpenAI-compatible shape.
      parameters:
      - $ref: '#/components/parameters/ProjectIdHeader'
      responses:
        '200':
          description: The list of available models.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ModelList'
        '401':
          $ref: '#/components/responses/Unauthorized'
components:
  schemas:
    Model:
      type: object
      properties:
        id:
          type: string
          example: openai/gpt-4o
        object:
          type: string
          example: model
        owned_by:
          type: string
        provider:
          type: string
    ModelList:
      type: object
      properties:
        object:
          type: string
          example: list
        data:
          type: array
          items:
            $ref: '#/components/schemas/Model'
    Error:
      type: object
      properties:
        error:
          type: object
          properties:
            message:
              type: string
            type:
              type: string
            code:
              type: string
  responses:
    Unauthorized:
      description: Missing or invalid API key.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
  parameters:
    ProjectIdHeader:
      name: X-Project-Id
      in: header
      required: false
      description: LangDB project id. Optional when the project id is embedded in the request path.
      schema:
        type: string
  securitySchemes:
    bearerAuth:
      type: http
      scheme: bearer
      bearerFormat: JWT
      description: 'LangDB API key (project access token) sent as `Authorization: Bearer <token>`.'