aidenybai/react-scan

What is it?

Key features

• 01Highlights components that re-render unnecessarily on the page
• 02Requires no code changes when added via script tag
• 03Provides an on-page toolbar for inspecting renders
• 04Offers scan, useScan, and setOptions APIs for programmatic control
• 05Lets you hook into renders of a specific component with onRender
• 06Includes a browser extension and framework setup guides

Use cases

• Finding wasteful re-renders in a slow React single-page app
• Checking which components re-render after a state change during development
• Auditing a Next.js or Remix project for unnecessary render work
• Tracking renders of a single component with the onRender hook

Quick start

1. 1

   Run the init command to auto-detect your framework and set up React Scan

   npx -y react-scan@latest init
2. 2

   Or install the package manually via npm

   npm install -D react-scan
3. 3

   Add the script tag to your app (e.g. index.html, before any scripts)

Things to know

• !The README recommends React Doctor as the successor, so React Scan may receive less active development focus.
• !Manual setup requires adding a script tag or framework-specific code, and the script loads from unpkg.com.

Topics

FAQ

What is react-scan?

A React performance tool that automatically detects and highlights components causing unnecessary re-renders, with no code changes required. React Scan finds performance problems in React applications by watching renders and highlighting the components that re-render unnecessarily. It is added with a single script tag or an npm package, so it works without changing application code.

Is react-scan free to use? What license does it have?

react-scan is open source under the MIT license. Check the license terms before using it in commercial products.

Is react-scan still maintained?

Updated within 6 months. The last commit to react-scan was on Aug 16, 2026.

What can I use react-scan for?

Finding wasteful re-renders in a slow React single-page app Checking which components re-render after a state change during development Auditing a Next.js or Remix project for unnecessary render work Tracking renders of a single component with the onRender hook

How do I install react-scan?

Run the init command to auto-detect your framework and set up React Scan: npx -y react-scan@latest init Or install the package manually via npm: npm install -D react-scan Add the script tag to your app (e.g. index.html, before any scripts)

Where can I get react-scan?

The source code and installation instructions are on GitHub: https://github.com/aidenybai/react-scan