builtwith.com

# BuiltWith

> Find out what websites are built with.

BuiltWith detects the technologies used on any website including CMS, ecommerce platforms, analytics,
frameworks, hosting providers, and more.

## Start Here (For LLMs and AI Agents)

Use the API-focused LLM guide first:
- https://api.builtwith.com/llms.txt

For BuiltWith knowledge-base guidance, see https://kb.builtwith.com/llms.txt.

This file is a high-level product map. The API LLM guide above contains detailed endpoint usage.
A full version of this product map is at https://builtwith.com/llms-full.txt and the full API
reference is at https://api.builtwith.com/llms-full.txt.

Choose an access method:
- BuiltWith API key: normal REST or standard MCP tools; calls spend account API credits.
- Existing account with a saved Stripe method: Agent Stripe Credit Top-Up API; this is not x402.
- Base USDC without a BuiltWith account: x402 v2 at https://api.builtwith.com/x402-api, using either one-off `/agent/*` HTTP payments or prepaid MCP lookup units.

## Core BuiltWith Links

- Website lookup: `https://builtwith.com/[domain]`
  - Example: https://builtwith.com/example.org
- Natural language Ask tool: https://builtwith.com/ask
- Technology trends and market movement: https://trends.builtwith.com
- MCP endpoint for AI integration: https://api.builtwith.com/mcp
- API LLM guide (primary): https://api.builtwith.com/llms.txt

## Discovery Endpoints

BuiltWith publishes the following `.well-known` resources for agents, API clients, and integration discovery:

- Agent Skills Discovery index: https://builtwith.com/.well-known/agent-skills/index.json
- BuiltWith API agent skill: https://builtwith.com/.well-known/agent-skills/builtwith-api/SKILL.md
- MCP discovery manifest: https://builtwith.com/.well-known/mcp.json
- Agent card: https://builtwith.com/.well-known/agent-card.json
  - Legacy A2A alias: https://builtwith.com/.well-known/agent.json
- API catalog: https://builtwith.com/.well-known/api-catalog
- x402 v2 payment discovery: https://api.builtwith.com/.well-known/x402
  - `https://builtwith.com/.well-known/x402` redirects to the canonical API-host descriptor.
- OAuth authorization server metadata: https://builtwith.com/.well-known/oauth-authorization-server
- OAuth protected resource metadata: https://builtwith.com/.well-known/oauth-protected-resource
- OpenAI plugin/app manifest: https://builtwith.com/.well-known/openai.json
- HTTP message signatures directory: https://builtwith.com/.well-known/http-message-signatures-directory
- Security contact policy: https://builtwith.com/.well-known/security.txt

## MCP Registry

A directory of remote Model Context Protocol servers BuiltWith has detected on company websites,
discovered from each site's published `llms.txt`. Every server and every tool has its own page.

- Registry home: https://builtwith.com/mcp-registry
- Category: `https://builtwith.com/mcp-registry/[category-slug]`
  - Example: https://builtwith.com/mcp-registry/developer-tools
  - Newest discoveries: https://builtwith.com/mcp-registry/recently-added
- Search: `https://builtwith.com/mcp-registry?search=[term]` - matches domains, endpoint URLs,
  tool names and tool descriptions
- Single MCP server: `https://builtwith.com/mcp/[domain]`
  - Example: https://builtwith.com/mcp/globalsurfari.com
- Single MCP tool: `https://builtwith.com/mcp/[domain]/tool/[tool-slug]`
- Sitemap for all of the above: https://builtwith.com/mcp-sitemap.xml
- Bulk and programmatic access: https://api.builtwith.com/mcp-api

Categories: developer-tools, api-tools, ai---machine-learning, productivity, analytics,
security---testing, devops, data-collection, general-tools, learning-resources, databases,
content-tools, cloud-services, collaboration, design, browser-tools, marketing, ecommerce,
social-media, game-development.

## Agent Stripe Credit Top-Up Endpoints (Not x402)

These legacy mppx paths charge an existing account's saved Stripe payment method and add account API credits. They are path aliases, not an x402 or MPP payment-challenge protocol.

- Credit balance: `GET https://api.builtwith.com/mppx/api-discovery`
- Spending limits: `GET https://api.builtwith.com/mppx/api-configuration`
- Credit purchase: `POST https://api.builtwith.com/mppx/api-purchase` with a unique `Idempotency-Key`; quantities use fixed increments of 2,000.
- Auth: separately scoped Agent Billing Key in `Authorization: Bearer`; general API keys and temporary `bw-` tokens cannot purchase. Monthly limits reset in UTC.
- Local OpenAPI discovery: `GET https://api.builtwith.com/mppx/openapi.json`
- BuiltWith.com aliases:
  - `GET https://builtwith.com/mppx/api-discovery`
  - `GET https://builtwith.com/mppx/api-configuration`
  - `POST https://builtwith.com/mppx/api-purchase`
  - `GET https://builtwith.com/mppx/openapi.json`

## x402 Paid Access

BuiltWith supports accountless x402 v2 access through prepaid MCP lookup units and fixed-price HTTP routes. These lookup units are separate from account API credits.

- Human documentation: `GET https://api.builtwith.com/x402-api`
- Canonical configuration and live pricing: `GET https://api.builtwith.com/.well-known/x402`
- MCP endpoint: `https://api.builtwith.com/mcp`
- Prepaid MCP flow: call `x402-pricing`, purchase at least 2,000 non-expiring lookup units with `x402-credit-purchase`, then pass the returned reusable `creditKey` to an `x402-*` lookup tool. Payment proof is sent in MCP request metadata at `_meta["x402/payment"]` only for purchases.
- One-off HTTP flow: discover the 12 fixed-price API routes and two List-pass purchase routes at `GET https://api.builtwith.com/openapi.json`. Send the intended query/body, read `PAYMENT-REQUIRED`, and retry the identical request with `PAYMENT-SIGNATURE`; successful settlement returns `PAYMENT-RESPONSE`.
- The descriptor is authoritative for the facilitator, network, asset, payment address, available tools, volume tiers, and List passes; clients should not hard-code those values.

## Programmatic Access

For direct API requests, use the official API docs and endpoint details:
- https://api.builtwith.com

Popular API families include:
- Domain technology lookup
- Technology and company lists
- Relationships / related sites
- Trust and risk signals
- Redirect and keyword data
- API-based trends data

## Notes

- Bots/AI agents may be blocked on interactive website pages.
- For reliable automated access, use the API and MCP routes.