What Is shadcn/ui?
Libraryshadcn/ui is a collection of accessible React components built on Radix UI primitives and styled with Tailwind CSS. Rather than installing a package, developers copy the component source into their project with a CLI, which makes it easy to customise. It is the default component kit of v0, Lovable, Bolt and most AI coding-assistant templates, so it is one of the more informative supporting signals this scanner tracks.
Detect shadcn/ui on any website:
Why shadcn/ui Matters
Libraries and third-party services are where a site's real behaviour lives: analytics, payments, auth, UI components and animation all arrive as scripts the browser can see. Knowing that shadcn/ui is on a page tells you about its dependencies, its privacy footprint, and sometimes its build pipeline — and it helps you tell template-driven stacks from hand-assembled ones. We've fingerprinted shadcn/ui on 30 live sites in our database, so the answers here are grounded in real scan data — not marketing copy.
Does shadcn/ui Mean a Site Was Built With AI?
shadcn/ui on its own does not prove AI involvement.
One of the most common outputs of AI website/app builders and AI coding assistants — a moderately useful signal, stronger when combined with other evidence.
How this feeds the score: builder fingerprints, bundle artifacts and AI-tool traces are weighed separately from stack context like frameworks, libraries and hosting. The full breakdown is on How scores work.
How Websites Using shadcn/ui Work
- Radix data attributes (`data-radix-*`, `data-state`) combined with Tailwind utility classes and CSS variables like `--primary`
- `cn()` class merging via clsx + tailwind-merge; Lucide icons by default
- Theme tokens in `:root` (`--background`, `--foreground`, `--radius`)
- Appears in hand-written projects too — a moderate signal that strengthens when paired with Supabase, Vite and a Lovable/Bolt bundle
Best Practices When Working With shadcn/ui
Based on patterns in our scan dataset and the detection evidence tiers.
- →Start by running a shadcn/ui detection scan on any URL you're evaluating — the 80+ signal engine returns a confidence score plus the exact markers it matched, which beats reading view-source by hand.
- →Cross-check the result against the full detection evidence in /how-scores-work — confidence tiers tell you whether a match is strong (headers + scripts) or circumstantial (a single HTML pattern).
How we detect shadcn/ui — see our methodology: AI Influence Score calculation, evidence tiers, and fingerprint signal types.
How Our Detector Identifies shadcn/ui
Our scanner analyzes multiple layers of a website's technical fingerprint to detect shadcn/ui usage.
- HTML structure patterns such as "--radius: [N.]+rem", "data-[state=open]", "cmdk-" (medium-confidence tier)
- Signal weights for shadcn/ui: 80 points per high-tier match, 55 per medium, 25 per low — a site needs 60+ points before shadcn/ui is reported.
Websites Built With shadcn/ui
Real sites detected by our scanner
What shadcn/ui Sites Usually Run Alongside
Technologies detected on the same domains as shadcn/ui in our most recent scans. Counts are unique domains, not page views.
Frequently Asked Questions About shadcn/ui
What is shadcn/ui?+
shadcn/ui is a collection of accessible React components built on Radix UI primitives and styled with Tailwind CSS. Rather than installing a package, developers copy the component source into their project with a CLI, which makes it easy to customise. It is the default component kit of v0, Lovable, Bolt and most AI coding-assistant templates, so it is one of the more informative supporting signals this scanner tracks.
Does shadcn/ui mean a website was built with AI?+
shadcn/ui on its own does not prove AI involvement. One of the most common outputs of AI website/app builders and AI coding assistants — a moderately useful signal, stronger when combined with other evidence.
Why does shadcn/ui matter?+
Libraries and third-party services are where a site's real behaviour lives: analytics, payments, auth, UI components and animation all arrive as scripts the browser can see. Knowing that shadcn/ui is on a page tells you about its dependencies, its privacy footprint, and sometimes its build pipeline — and it helps you tell template-driven stacks from hand-assembled ones. We've fingerprinted shadcn/ui on 30 live sites in our database, so the answers here are grounded in real scan data — not marketing copy.
How do we detect shadcn/ui?+
Our scanner checks for these signals: HTML structure patterns such as "--radius: [N.]+rem", "data-[state=open]", "cmdk-" (medium-confidence tier); Signal weights for shadcn/ui: 80 points per high-tier match, 55 per medium, 25 per low — a site needs 60+ points before shadcn/ui is reported.. Each match contributes to a confidence score, and the full evidence tiers are documented at /how-scores-work.
How many websites using shadcn/ui are in the database?+
We've fingerprinted 30+ live sites built with shadcn/ui across our scan dataset. The list refreshes as new scans come in.
What are the typical characteristics of a shadcn/ui website?+
Radix data attributes (`data-radix-*`, `data-state`) combined with Tailwind utility classes and CSS variables like `--primary`. `cn()` class merging via clsx + tailwind-merge; Lucide icons by default. Theme tokens in `:root` (`--background`, `--foreground`, `--radius`). Appears in hand-written projects too — a moderate signal that strengthens when paired with Supabase, Vite and a Lovable/Bolt bundle
Related Tools & Technologies
Other libraries and services we detect
Ready to put shadcn/ui detection to work?
You now know what shadcn/ui is, why it matters, how to spot it, and where the detection signals come from. The next step is using that knowledge on a real URL — yours, a competitor's, or a prospect's.