What is React?
React is a JavaScript library for building user interfaces.
Signs a site uses React
- An empty root element in the source. Single-page React apps often send almost no content, such as a div with the id root, and build the page in the browser.
- data-reactroot on older sites. Older React versions added this attribute to the page.
- React internals on page elements. In the browser console, elements carry properties that begin with __react.
How to check by hand
Install the React Developer Tools browser extension. Its icon lights up on React sites, which makes it the most reliable manual check.
What can hide it
React is compiled into ordinary JavaScript, so it’s hard to detect from source alone. A site built with a framework may show that framework instead. A negative result doesn’t prove a site isn’t using React, because the checker reads the page source and response headers, and tools loaded later by JavaScript may be missed.
Check the rest of the stack
Paste the address into the Website Technology Checker to see the platform, framework, analytics and more in one report. To see where the site runs, use Who Is Hosting.
Website Technology CheckerFind out what any site runs on: CMS (WordPress, Drupal, Joomla, Ghost, Webflow, Wix, Shopify), forum software (vBulletin, XenForo, phpBB, Discourse), frameworks (Next.js, Nuxt, React, Vue), server and CDN, analytics and more — with versions when the site shows them.
Open the tool Frequently asked questions
How can I tell if a website uses React?
Enter the address in the checker above, or view the page source and look for: An empty root element in the source.
Is the React check always accurate?
A match is a strong sign, but no outside check is certain. React is compiled into ordinary JavaScript, so it’s hard to detect from source alone. A site built with a framework may show that framework instead.
Is React a framework?
React itself is a library. Frameworks such as Next.js are built on top of it and add routing and server rendering.