You have a list of domains. A conference attendee export, a directory scrape, a spreadsheet from a colleague.

You want to know which of them run Shopify, which run WordPress, which have HubSpot installed, and which are on

Cloudflare. That single question sits behind a lot of sales prospecting, competitor tracking and agency audits.

The mechanics are not complicated, and it is worth understanding them before you decide whether to build or buy.

What a website tells you without being asked