How to tell if a website was built with AI
You cannot tell by looking at a site. Style is not evidence: a careful person produces clean, generic pages too, and a good designer can make an AI-built site look bespoke. What does tell you is what the tool left in the code, and that is checkable.
Here is the order to check things in, from conclusive to suggestive. Everything in the first group names a specific tool; everything after it is a habit, not proof.
1. The generator meta tag (conclusive)
Open the page source and search for generator. Builders write their own name there: v0.app, Framer, Wix, Webflow, Squarespace. It is one line, and it is the tool telling you itself.
2. Script and asset hosts (conclusive)
Look at where the page loads its files from. gpteng.co is Lovable. media.base44.com is Base44. A host you do not recognise, serving the site’s own images or scripts, is usually the platform that built it, and it survives a move to a custom domain.
3. The address itself (conclusive while it lasts)
Anything on *.lovable.app, *.bolt.host, *.replit.app, *.base44.app or v0-*.vercel.app is that builder’s own hosting. A custom domain removes this signal, which is why the first two matter more.
4. Inside the JavaScript bundle (conclusive)
Open the main file under /assets/ and search for the builder’s name, or for keys like base44_access_token. This is also where you find the real problem on many AI-built sites: an API key shipped to the browser. In our scans, a Supabase key in the bundle is the single most common critical finding.
5. Habits, not proof
Default class vocabularies left unrenamed, data-testid attributes shipped to production, deeply nested wrapper elements, an empty HTML shell that renders itself with JavaScript, a missing canonical URL, "Lorem ipsum" or "Your Company" still in the copy.
None of these prove a machine wrote the page. Together they raise the odds, which is why a serious answer weighs them rather than treating any one as a verdict. A site with no builder fingerprint at all is reported here as "No AI builder detected", even when it looks generated, because a guess is not an answer.
Questions
Can an AI detector tell me if the text was written by AI?
That is a different question, and the tools that claim to answer it are language models guessing, with false positives on ordinary writing. This page is about how the site was built, which leaves physical traces in the code.
What if the site was exported off the builder?
Then there is often nothing left to find. A Bolt or v0 project exported and hosted elsewhere can be indistinguishable from hand-written code, and the honest answer is that it cannot be determined.
Does it matter whether a site was built with AI?
For the visitor, rarely. For whoever owns it, yes: AI-built sites share a set of predictable problems, from keys in the bundle to an empty page for crawlers, and knowing the tool tells you which ones to check first.
Is there a faster way than checking by hand?
Paste the URL above. The scanner runs every rule server-side and shows you which ones matched, where, and the exact text it found, so you can verify the verdict rather than take it on trust.