11 signs a website was built with AI

Once you've seen a few, you can't stop seeing them. None of these proves anything on its own, and plenty of good sites use one or two on purpose. It's the combination that gives it away, and the feeling that nobody decided any of it.

The visual tells

• A purple or indigo gradient, often on the headline text.
• Inter or the system font for everything, with no second voice.
• A pill badge above a centred title, then two buttons.
• Three identical cards with an icon or emoji on each.
• The same radius and the same soft shadow on everything, with cards inside cards.
• Blurred glass panels and glows that aren't doing anything.
• The same fade and slide on every section.

The second wave

These appeared when people started telling models to avoid the first list, and now they're tells of their own: cream background with a serif and a terracotta accent, near-black with one neon colour, tiny all-caps labels with monospace details, and a single italic word in the headline.

The words

• Generic buttons and headlines that could be about any product.
• Numbers nobody can source: 10x, 99%, thousands of happy teams.
• No real proof: no product screenshots, customers or people.
• Stock phrasing in every section, with an emoji at the start of each bullet.

What's not a sign

Hosting and framework details tell you very little. A Vercel header or Framer attribute identifies a platform, and huge numbers of hand-built sites use them. AI detection tools exist, but they're sold by the people who benefit from you trusting them, so treat their scores with care.

It also runs the other way. A Canadian government test found people were suspicious of AI images on pages where no images were AI generated at all. People are worse at this than they think.

Do visitors actually care?

Here we have to be careful, because a lot of confident numbers on this topic trace back to nothing. Three things we can point to:

• Looks affect credibility. In a Stanford study led by B.J. Fogg, 2,684 people assessed live sites, and design was the most mentioned factor, in 46.1% of their comments. It's over twenty years old, but still the classic reference.
• First impressions are fast. Lindgaard and colleagues found people form a stable view of a page's visual appeal in about 50 milliseconds.
• Poor sites can read as fake. In a 2026 Pantheon survey of 1,000 US adults, 72% said a badly performing site makes them suspect it's unsafe or fake, and outdated design was among the reasons given. It's a vendor survey, and it's about performance more than style.

What we couldn't find is a good study measuring whether AI-styled design, specifically, costs conversions. Anyone giving you a figure for that should show you the source. Our honest read: people judge quickly, and a page that looks like a thousand others gives them no reason to think yours is different.

If your site has these

None of it is hard to change. Start with the guide on making a vibe-coded site look professional, and begin with your actual product on the page. That single change removes more of the feeling than any colour.