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Is This Website Built With React?

Paste any URL below. Our scanner checks 11 React-specific fingerprints — scripts, CDN domains, HTML attributes, and HTTP headers — and returns a confidence score instantly.

How to Tell if a Website Uses React

Identifying whether a website was built with React used to require technical expertise — inspecting source code, tracing network requests in DevTools, and knowing which patterns to look for. Our free scanner automates all of that: it fetches the page, analyzes 11 React-specific signals, and returns a verdict with a confidence score.

You might want to detect React for competitive research, due diligence before acquiring a site, or simple curiosity. Whatever the reason, this page covers every method — automated and manual.

What is React?

React is a AI Coding Tool used to build websites and web applications.

It is primarily used for powering websites built by developers using AI coding assistants or modern JavaScript frameworks.

Visit React official website

Signs a Website Is Built With React

Our detection engine checks 11 unique React fingerprints. Here are the most reliable signals:

High Confidence

CDN Domain

Assets (images, scripts, fonts) are loaded from React-specific CDN domains. This is one of the most reliable signals because CDN domains are hard to hide.

unpkg.com/reactcdn.jsdelivr.net/npm/reactesm.sh/react
High Confidence

JavaScript / Script Files

React loads specific JavaScript runtime files or loads scripts from identifiable URLs. Checking script src attributes reveals the platform.

react-domreact.min.jsreact.production.min.js
Medium Confidence

HTML Attributes & Class Names

React injects proprietary class names, data attributes, or markup patterns into the page HTML that are unique to the platform.

data-reactroot__reactFiber__reactProps

How to Manually Detect React Websites

Method 1 — View Page Source

  1. Open the website in your browser
  2. Press Ctrl+U (Windows) or Cmd+Option+U (Mac)
  3. Search (Ctrl+F) for react or react
  4. If found in script src, class names, or meta tags — it's likely React

Method 2 — Browser DevTools Network Tab

  1. Press F12 to open DevTools
  2. Click the Network tab and reload the page
  3. Filter by react in the search box
  4. If you see requests to React-specific domains, it's confirmed
Faster: Skip the manual steps — paste the URL into our scanner above and we check all 11 signals in seconds.

How Our React Detector Works

When you submit a URL, our engine fetches the page from its server — just like a browser would — then analyzes the response across 11 React-specific fingerprints:

Script analysis

We scan all loaded JavaScript files for known CDN paths and runtime names

CDN domain matching

We cross-reference every asset request against known platform CDNs

HTML pattern scanning

We search the DOM for platform-specific class names and data attributes

Header inspection

We read HTTP response headers that identify the server or platform

Meta tag extraction

We check generator and other meta tags in the document head

Confidence scoring

We weight each matched signal and normalize to a 0–99% score

How to Build a Similar Website With React

React is a developer tool. To build a site with it, install it via npm/yarn, initialize a project, and follow the official documentation at https://react.dev.

Other popular frameworks and coding tools include Next.js, Astro, SvelteKit, Remix, and Gatsby.

Get started with React

Frequently Asked Questions

How can I tell if a website was built with React?

The most reliable ways to detect React are: (1) open DevTools → Network tab and look for requests to React-specific CDN domains, (2) view page source and search for React-specific class names or data attributes, (3) use our free scanner — we check 11 detection signals automatically and return a confidence score.

Is your React detector free?

Yes, completely free. Paste any URL into our scanner and we'll analyze it for React fingerprints immediately. No account required, no limits on scans.

How accurate is the React detection?

We check 11 unique React fingerprint signals across HTML, JavaScript, CDN domains, meta tags, and HTTP headers. Our confidence score reflects how many signals matched — a score above 70% is a strong indicator. We cap accuracy at 99% to reflect that all fingerprint-based detection is probabilistic.

Can React sites be detected if they use a custom domain?

Yes. Custom domains don't hide the underlying platform. The JavaScript files, CDN requests, HTML attributes, and server headers all remain identifiable regardless of the domain name used. Our scanner fetches the page directly and analyzes its technical composition.

What should I do after detecting a React website?

If you want to build something similar, visit https://react.dev to learn more or sign up. If you're doing competitive research, our scan result also shows the full technology stack — including hosting platform, domain age, and other detected technologies. You can share the result link with your team.