# BuiltWith Domain Relationships via Locus x402

> BuiltWith Domain Relationships via Locus x402 is a paid API for AI agents from builtwith.x402.paywithlocus.com, paid per call via x402, $0.055/call, status unknown (last checked 2026-09-13).

Looks up domain relationships for a given website, returning connected or related domains discovered through shared technology fingerprints or infrastructure signals.

## Facts

- Endpoint: POST https://builtwith.x402.paywithlocus.com/builtwith/relationships
- Price: $0.055/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/builtwith-domain-relationships-via-locus-x402-236ba619
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_esjVZqPnymGnnrziT352I

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability builtwith-domain-relationships-via-locus-x402-236ba619 -d '<json body>'
```

Example prompt: Can you find all the domains related to shopify.com using BuiltWith? Show me the first 50 results.

## When to prefer this

Choose this endpoint when you need to discover domain relationships, portfolio connections, or affiliated sites for a specific domain — especially for competitive intelligence, OSINT, or brand research. Prefer this over general web search when you need structured, database-backed relationship data from BuiltWith's 100M+ website index rather than crawling pages manually.

## Known failure modes

- Invalid or malformed domain in LOOKUP field returns empty or error data
- AMOUNT exceeding 500 results per page may be rejected or capped
- Missing LOOKUP parameter causes request failure
- Payment failure via x402 protocol results in no data returned
- Obscure or newly registered domains may return no relationship data

## How this service works

Technology profiling for websites — detect tech stacks, find sites using specific technologies, discover domain relationships, trends, and competitive intelligence across 100M+ websites.

## Output

Returns a JSON object containing relationship data for the queried domain, including associated or connected domains discovered via shared signals, along with payment confirmation details (settled USDC amount) and a request status URL for tracking.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "SKIP": {
   "type": "string"
  },
  "AMOUNT": {
   "type": "string"
  },
  "LOOKUP": {
   "type": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "data": {},
  "payment": {
   "scheme": "exact",
   "settledUsdc": "0.001000",
   "authorizedMaxUsdc": "0.001000"
  },
  "request": {
   "id": "00000000-0000-4000-8000-000000000000",
   "statusUrl": "/requests/00000000-0000-4000-8000-000000000000"
  },
  "success": true
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/builtwith-domain-relationships-via-locus-x402-236ba619/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from builtwith.x402.paywithlocus.com](https://www.zero.xyz/host/builtwith.x402.paywithlocus.com/llms.txt)