Coverage and limits

Where the data is strong, where it is not, and what we cannot see at all.

What we observe

Technology detection comes from HTTP Archive, which crawls sites in the Chrome UX Report monthly. That gives roughly 12.1M registrable domains. Our profiled set is the top 1,000,000 by CrUX rank, which is where our coverage is competitive.

Where we are weaker than competitors

Coverage. Vendors running their own crawler index more sites. We hold 46–65% of BuiltWith's top-1M counts on the technologies we have compared.
Freshness. Monthly crawl, published 4–6 weeks after the month it covers.
Large organisations. Coverage falls sharply at the very top: enterprises run marketing and commerce stacks on subdomains that a homepage crawl never sees. This data is strongest in the mid-market.
Contact data. We do not source contacts. We verify addresses you already have.

Field fill rates

Contact fields come from each prospect's own structured data and are sparse. Measured, current:

technology_stack100.00%
description50.66%
social12.71%
title10.56%
phone3.94%
linkedin_url3.52%
locality3.39%
A 3.9% phone column is not a phone column. These rates ship in every response so a sparse field is never mistaken for a full one.

What we cannot see

Databases, warehouses and server-side infrastructure — anything invisible to a rendered page. Sites below the CrUX inclusion threshold. Technology on subdomains and behind logins. Multi-tenant registrable domains are flagged and excluded, because their merged stack belongs to nobody.