What is this website built with?

Paste its address above. The checker reads what the site gives away to any visitor: response headers such as x-powered-by or x-vercel-id, the cookies it sets, where its scripts load from, the generator tag, framework fingerprints in the HTML (/_next/static/, /wp-content/), and its DNS records.

By hand, the same evidence is in your browser’s developer tools: the Network tab shows the headers, and “View source” shows the scripts and markup.

Sometimes. A site still served from a builder’s own address (something.lovable.app, something.replit.app) or still loading the builder’s scripts is called out at the top of the result. A project that was exported and deployed elsewhere usually looks like any other React or Next.js site — so “no sign of an AI builder” is not proof that none was used.

Anything that never reaches the browser leaves no trace in a page: the database, most backend languages, the CI pipeline, the AI model behind an API. Some of these are filled in when something found cannot run without them (WordPress implies PHP). Sites that build the whole page in JavaScript after it loads, or that sit behind bot protection, also show less.

The brand appears somewhere in the page — a “Powered by” link, a logo strip of customers, a blog post — but nothing technical confirms the site runs on it. Those are listed apart so they never pass for a finding.

It is free, needs no extension or account, and shows the evidence for every finding. It also compares the stack with the indie products launched on Awesome Indie’s built-with pages: how many use each technology, and which ones share the most of this stack. It does not keep a history of sites or sell lead lists.

Yes. The checker makes one ordinary request for the page, exactly like a visitor’s browser, and reads only what the site sends to everyone. Nothing is logged in, probed or scanned.