BuiltWith

BuiltWith Tag Lookup API

Lookup domains by IP or attribute identifier

Documentation GitHub OpenAPI

Operations 2

GET /api.json Get domains by tag/attribute (JSON) #

GET /api.xml Get domains by tag/attribute (XML) #

Specifications

⚙

OpenAPI

https://raw.githubusercontent.com/api-evangelist/builtwith/refs/heads/main/openapi/builtwith-tag-lookup-api-openapi.yml

Work with this as data

Every API here is available over the APIs.io API and to AI agents over MCP.

MCP server

One button, every client — Claude, Cursor, VS Code and the rest.

https://apis.io/mcp

Tools for apis

7 MCP tools reach this

find_apisBrowse and filter every API in the catalog.
get_api_artifactsOne API's artifacts, grouped by type.
get_openapiThe primary OpenAPI for this API.
find_similar_apisAPIs that look like this one.
apis_io_searchSTART HERE — APIs, providers and tags for one query, each with its total.
resolveTurn a domain, URL or GitHub org into the provider it belongs to.
find_cohortsEvery scored population of providers in the catalog.

All 92 tools →

Call it yourself

curl for this page

This API

curl "https://apis.io/api/v1/apis/builtwith-tag-lookup-api"

All apis

curl "https://apis.io/api/v1/apis?limit=25"

Discovery needs no key. Ratings and market analysis are Pro.

Get an API key

Free tier, no form to fill in. Signing in shares your email address with us — we store it to create your key and to recognise you if you sign in with another provider. See our Privacy Policy and Terms.

GitHub Google LinkedIn

A second provider on the same verified email joins the account you already have.

OpenAPI Specification

openapi: 3.2.0
info:
  title: BuiltWith Change Bulk Processing Tag Lookup API
  description: 'Track technology additions and removals on websites with business context. Returns AI-generated summaries explaining the business significance of technology changes. Credits are only consumed when changes are found.

    '
  version: change1
  contact:
    name: BuiltWith Support
    url: https://builtwith.com/contact
  termsOfService: https://builtwith.com/terms
  license:
    name: Commercial
    url: https://builtwith.com/plans
servers:
- url: https://api.builtwith.com/change1
  description: BuiltWith Change API v1
security:
- apiKeyQuery: []
- apiKeyHeader: []
tags:
- name: Tag Lookup
  description: Lookup domains by IP or attribute identifier
paths:
  /api.json:
    get:
      summary: Get domains by tag/attribute (JSON)
      description: 'Returns domains associated with the given attribute (IP address, publisher ID, etc.). Supports up to 16 comma-separated attribute values. Use TYPES=true to retrieve the list of available attribute types.

        '
      operationId: getTagDomainsJson
      tags:
      - Tag Lookup
      parameters:
      - $ref: '#/components/parameters/KEY'
      - $ref: '#/components/parameters/LOOKUP'
      - $ref: '#/components/parameters/TYPES'
      responses:
        '200':
          description: Domains matching the attribute or list of attribute types
          content:
            application/json:
              schema:
                oneOf:
                - $ref: '#/components/schemas/TagResult'
                - $ref: '#/components/schemas/TypesResult'
              example:
                Identifiers:
                - Value: IP-98.158.194.127
                  Matches:
                  - Domain: example.com
                    First: '2020-01-01'
                    Last: '2026-06-01'
                  - Domain: example2.com
                    First: '2021-03-15'
                    Last: '2025-12-01'
        '400':
          $ref: '#/components/responses/BadRequest'
        '401':
          $ref: '#/components/responses/Unauthorized'
  /api.xml:
    get:
      summary: Get domains by tag/attribute (XML)
      operationId: getTagDomainsXml
      tags:
      - Tag Lookup
      parameters:
      - $ref: '#/components/parameters/KEY'
      - $ref: '#/components/parameters/LOOKUP'
      - $ref: '#/components/parameters/TYPES'
      responses:
        '200':
          description: Tag domains in XML
          content:
            application/xml:
              schema:
                type: object
components:
  parameters:
    KEY:
      name: KEY
      in: query
      required: false
      schema:
        type: string
        format: uuid
        example: 00000000-0000-0000-0000-000000000000
    LOOKUP:
      name: LOOKUP
      in: query
      description: 'Attribute value(s) to query, prefix with type (e.g. IP-98.158.194.127 or CA-PUB-1894893914772263). Up to 16 comma-separated values.

        '
      required: false
      schema:
        type: string
        example: IP-98.158.194.127
    TYPES:
      name: TYPES
      in: query
      description: Set to 'true' to return list of available attribute types
      required: false
      schema:
        type: string
        enum:
        - 'true'
  schemas:
    TypesResult:
      type: object
      description: Available attribute types
      properties:
        Types:
          type: array
          items:
            type: object
            properties:
              Type:
                type: string
                description: Attribute type identifier
              Description:
                type: string
                description: Human-readable description of the attribute type
    TagIdentifier:
      type: object
      properties:
        Value:
          type: string
          description: The queried attribute value
          example: IP-98.158.194.127
        Matches:
          type: array
          items:
            $ref: '#/components/schemas/TagMatch'
    TagMatch:
      type: object
      properties:
        Domain:
          type: string
          description: Domain associated with the attribute
        First:
          type: string
          format: date
          description: First detection date (ISO 8601)
        Last:
          type: string
          format: date
          description: Last detection date (ISO 8601)
    ErrorResponse:
      type: object
      properties:
        Errors:
          type: array
          items:
            type: object
            properties:
              Code:
                type: integer
              Message:
                type: string
    TagResult:
      type: object
      description: Results for tag/attribute lookup
      properties:
        Identifiers:
          type: array
          items:
            $ref: '#/components/schemas/TagIdentifier'
  responses:
    Unauthorized:
      description: Unauthorized — invalid or missing API key
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/ErrorResponse'
    BadRequest:
      description: Bad request — invalid parameters
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/ErrorResponse'
  securitySchemes:
    apiKeyQuery:
      type: apiKey
      in: query
      name: KEY
    apiKeyHeader:
      type: apiKey
      in: header
      name: Authorization
      description: 'Format: ''Authorization: API {key}'''
externalDocs:
  description: BuiltWith Change API Documentation
  url: https://api.builtwith.com/change-api