openapi: 3.2.0
info:
  title: BuiltWith API (from llms.txt + samples) Agent Auth API
  version: '2026-05-08'
  description: OpenAPI spec generated from https://api.builtwith.com/llms.txt and sample payloads under https://api.builtwith.com/samples/*.json (where available). Endpoints not covered by a sample file use a generic JSON schema.
servers:
- url: https://api.builtwith.com
security:
- ApiKeyQuery: []
tags:
- name: AgentAuth
paths:
  /agent-auth/start:
    post:
      operationId: agent_auth_start
      tags:
      - AgentAuth
      summary: Start agent device-code authorization
      description: Starts a device-code authorization flow for AI agents. No API key is required.
      security: []
      responses:
        '200':
          description: Device authorization started.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/AgentAuthStartResponse'
  /agent-auth/token:
    post:
      operationId: agent_auth_token
      tags:
      - AgentAuth
      summary: Poll agent device-code authorization
      description: Poll no faster than the interval returned by agent_auth_start. Denied and expired responses use HTTP 400 and include a JSON body.
      security: []
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/AgentAuthTokenRequest'
      responses:
        '200':
          description: Token issued or authorization still pending.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/AgentAuthTokenResponse'
        '400':
          description: Access denied, expired token, or other authorization error.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/AgentAuthTokenResponse'
components:
  schemas:
    AgentAuthStartResponse:
      type: object
      required:
      - device_code
      - verification_uri
      - expires_in
      - interval
      properties:
        device_code:
          type: string
        verification_uri:
          type: string
          format: uri
        expires_in:
          type: integer
          format: int32
        interval:
          type: integer
          format: int32
      additionalProperties: true
    AgentAuthTokenResponse:
      type: object
      properties:
        access_token:
          type: string
          description: Temporary bw- prefixed API token when authorization succeeds.
        token_type:
          type: string
          example: bearer
        expires_in:
          type: integer
          format: int32
        error:
          type: string
          enum:
          - authorization_pending
          - access_denied
          - expired_token
      additionalProperties: true
    AgentAuthTokenRequest:
      type: object
      required:
      - device_code
      properties:
        device_code:
          type: string
      additionalProperties: false
  securitySchemes:
    ApiKeyQuery:
      type: apiKey
      in: query
      name: KEY
      description: BuiltWith API key (KEY).
    BearerAuth:
      type: http
      scheme: bearer
      description: BuiltWith API key or temporary bw- agent token in the Authorization header.
externalDocs:
  description: 'Source: BuiltWith llms.txt'
  url: https://api.builtwith.com/llms.txt
x-mcp:
  endpoint: https://api.builtwith.com/mcp
  server: builtwith
  version: 1.3.0
  transport: streamable-http
  tools:
  - domain-lookup
  - domain-api
  - domain-api-json
  - change-api
  - relationships-api
  - free-api
  - company-to-url
  - tags-api
  - recommendations-api
  - redirects-api
  - keywords-api
  - keywords-search-api
  - trends-api
  - product-api
  - trust-api
  - financial-api
  - social-api
  - payment-balance
  - payment-config
  - payment-purchase
  - vector-api
  - ask-api
  - ask-api-json
  resources:
  - ui://widget/domain-technologies.html
  - ui://widget/ask-sites.html
  prompts:
  - analyze-tech-stack
  - find-related-websites
  - get-technology-recommendations
  - research-company
  - check-domain-trust
  - discover-technologies-by-concept
x-live-feed-websocket:
  tag: LiveFeed
  servers:
  - url: wss://sync.builtwith.com
  connection_endpoints:
  - wss://sync.builtwith.com/wss/new?KEY=YOUR_KEY
  - wss://sync.builtwith.com/wss/channel/{TECH}?KEY=YOUR_KEY
  commands:
  - action: subscribe
    payload:
      action: subscribe
      channel: Shopify
  - action: unsubscribe
    payload:
      action: unsubscribe
      channel: Shopify
  - action: list_subscriptions
    payload:
      action: list_subscriptions