What is this website built with?

Paste the store address above. Every Shopify storefront publishes its theme name, its base theme and its version in the code it sends to the browser, and the detector reads them. You also see whether it is a Theme Store theme or a custom one, and whether it is an Online Store 2.0 theme.

The detector lists the apps that add code to the storefront: reviews, email and SMS, upsell, subscriptions, chat, search and page builders. Apps that only work in the Shopify admin or in checkout leave nothing visible, so no tool can list them from outside.

It covers the same basic question for one page at a time, free and without an account, and it shows the evidence for every result. Paid tools add history, whole-web lookups and lead lists, which this does not.

It loads one public page of the site, the way your browser does, and reads three things: the response headers, the cookies the site sets and the page code (scripts, files, meta tags). Each technology it lists comes with the exact thing it was recognised from.

A result marked "Confirmed" was found from something only that technology produces, such as its own generator tag, its own domain or its own JavaScript object. "Likely" means a strong hint that other tools can also produce. Anything that runs only on a server and sends nothing to the browser cannot be seen by any detector, including this one.

Only apps that add code to the storefront can be detected from outside. Apps that work in the admin, in checkout extensions or through the API leave no trace in the public page. Apps that are removed but left code behind may still show up.

It reads the theme name, the base theme name and the version the store publishes. A store that renamed or duplicated its theme shows the renamed name together with the base theme. Theme Store themes carry a store id, which is shown.

No. Nothing is saved: no list of sites, no results. The last answer for a site is kept in memory for ten minutes so that repeated checks are quick, then it is forgotten.

The usual reasons: the address is wrong, the site is down, it is behind a login or password, or a security service blocks automated visitors. Some blocked sites still reveal their CDN from the response headers.