mswjs

Industry standard API mocking for JavaScript.

Data querying library for testing JavaScript applications.

Mock Service Worker usage examples.

Low-level network interception library for Node.js.

Mock API requests in Storybook with Mock Service Worker.

Mock APIs in Playwright using Mock Service Worker.

Spawn an HTTP server from your request handlers or apply them to an existing server using a middleware.

A Fetch API "Headers" polyfill and transformation library.

Reliably determines if the code is running in Node.js. Treats Jest, React Native, Electron, and others like Node.js.

The "localStorage" polyfill for Node.js.