BuiltWith Tags Lookup via Locus x402

x402

BuiltWith Tags Lookup 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 2026-09-14).

Look up which websites use a specific technology tag or attribute, returning adoption data across 100M+ websites via the BuiltWith API.

Price / call$0.055

Seller volume →—

Success—

StatusUnknown

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 data object containing the list of websites or domains associated with the queried technology tag or IP attribute, including adoption counts and related metadata, along with payment settlement details confirming the USDC microtransaction.

Example use cases

Competitor tech stack discovery

“Can you look up which major websites are using the Klaviyo email marketing tag? I want to find ecommerce brands to target for our competing email tool.”

IP-based site attribution

“Find all websites associated with the IP prefix IP-104.21.0.0 using BuiltWith — I need to know what domains are hosted on that network.”

Sales prospecting by technology

“Pull a list of websites that have the HubSpot CRM tag installed — I'm building a prospect list for our sales team to reach out to HubSpot customers.”

Technical details

Endpoint

POSThttps://builtwith.x402.paywithlocus.com/builtwith/tags

When to prefer

Choose this endpoint when you need to discover which websites use a specific technology, plugin, tag, or attribute at scale across 100M+ websites. It is ideal for sales prospecting, competitive intelligence, and technology adoption research. Prefer this over manual web scraping or smaller tech-detection tools when breadth of coverage and structured attribute-based lookup are required. The x402 micropayment model makes it accessible per-call without subscription overhead.

Side effects

Invalid or unrecognized LOOKUP value returns empty data object
Missing LOOKUP field causes request error
IP address not prefixed with 'IP-' may not return IP-based results
Payment failure or insufficient USDC balance blocks the request
Rate limiting or quota exceeded on the BuiltWith API side
Rare tags with no known adopters return empty results

Input

Schema · Request body

Field	Type	Description
LOOKUP	string

Output

Schema · Response

{
  "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
  }
}

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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

Example use cases

Competitor tech stack discovery

“Can you look up which major websites are using the Klaviyo email marketing tag? I want to find ecommerce brands to target for our competing email tool.”

IP-based site attribution

“Find all websites associated with the IP prefix IP-104.21.0.0 using BuiltWith — I need to know what domains are hosted on that network.”

Sales prospecting by technology

“Pull a list of websites that have the HubSpot CRM tag installed — I'm building a prospect list for our sales team to reach out to HubSpot customers.”

Technical details

Endpoint

POSThttps://builtwith.x402.paywithlocus.com/builtwith/tags

When to prefer

Side effects

Invalid or unrecognized LOOKUP value returns empty data object
Missing LOOKUP field causes request error
IP address not prefixed with 'IP-' may not return IP-based results
Payment failure or insufficient USDC balance blocks the request
Rate limiting or quota exceeded on the BuiltWith API side
Rare tags with no known adopters return empty results

Input

Schema · Request body

Field	Type	Description
LOOKUP	string

Output

Schema · Response

{
  "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
  }
}