React is a declarative JavaScript library developed by Meta for building interactive user interfaces, widely adopted by startups, enterprise teams, and independent developers to power everything from single-page applications to complex web platforms. AIWebsiteDetector.com identifies React-powered sites through a combination of 4 distinct script patterns, 4 CDN domains, and 3 HTML patterns — including characteristic data attributes and DOM markers that React injects during rendering. These signals are cross-referenced against known React build artifacts and CDN delivery signatures to produce reliable detections across both production-minified and development builds. Because React is a frontend library rather than a full hosting platform, it frequently appears alongside other detectable technologies such as Next.js, Vite, or Webpack, making co-detection a common and useful signal for refining confidence scores. The official React documentation and release distribution are maintained at [react.dev](https://react.dev), and its presence on a site is technology-agnostic with respect to hosting provider — meaning React is detectable regardless of whether a site runs on Vercel, Netlify, AWS, or a self-hosted server.
Detect React Websites — Free Tool
Enter any URL to check if it was built with React. Instant results, no account required.
How we detect React — see our methodology: AI Influence Score calculation, evidence tiers, and fingerprint signal types.
How to Detect React Websites
Script Patterns
4 patterns
CDN Domains
4 patterns
HTML Patterns
3 patterns
1. Check the Page Source
Open the website in your browser, right-click, and select "View Page Source". Search for react-specific patterns in the HTML.
2. Look for Script Files
Check the Network tab in DevTools for JavaScript files loaded from React domains.
3. Check CDN Domains
Network requests to these CDN domains indicate a React site:
unpkg\.com\/reactcdn\.jsdelivr\.net\/npm\/reactesm\.sh\/reactcdn\.skypack\.dev\/react4. Use AI Website Detector (Easiest)
Our automated scanner checks all these signals at once and gives you an instant confidence score. Just enter any URL above.
Frequently Asked Questions
Is this website built with React?
You can detect if any website was built with React by using our free scanner above. Just enter the URL and we'll analyze HTML patterns, JavaScript files, CDN domains, and HTTP headers to determine if React was used — with a confidence score.
How to detect if a website was built with React?
There are several ways to detect React: (1) View the page source and look for React-specific class names or script URLs, (2) Check the Network tab in DevTools for requests to React CDN domains, (3) Use our free tool — we check 11 detection signals automatically.
What websites are built with React?
React is used by thousands of websites worldwide. Our scanner has detected many React-built sites across different industries. You can scan any URL to check if it uses React.
How accurate is the React detection?
Our React detection engine checks 11 unique fingerprint signals, achieving high confidence results. We score each match and return a confidence percentage so you know how certain the detection is.
About React
React is a leading ai coding tool used by thousands of businesses and developers worldwide. Our detection engine can identify React-built websites with high confidence by analyzing multiple technical signals.
Whether you're a developer doing competitive research, a designer looking for inspiration, or just curious about how a website was built — AI Website Detector gives you instant, accurate detection.
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Detection Info
- Category
- AI Coding Tool
- Signals Used
- 11 patterns
- Accuracy
- High
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