Mock Service Worker

Try it in 3 steps

1. 1

   Add v3.0.2 to an isolated project

   Use Node.js 22.12.0 or later and install the reviewed version in a small project.

   mkdir -p msw-demo && cd msw-demo && npm init -y && npm install msw@3.0.2Copy
2. 2

   Create a Node.js request handler

   Save a minimal example that returns JSON for a GET request without contacting an external service.

   printf '%s\n' "import { http, HttpResponse } from 'msw/http'" "import { setupServer } from 'msw/node'" "const server = setupServer(http.get('https://example.test/user', () => HttpResponse.json({ name: 'Ada' })))" "server.listen({ onUnhandledRequest: 'error' })" "const response = await fetch('https://example.test/user')" "console.log(await response.json())" "server.close()" > demo.mjsCopy
3. 3

   Check the mocked response

   Confirm that a normal fetch call receives { name: 'Ada' }.

   node demo.mjsCopy

Built with

• TypeScript

Categories and tags

GitHub data

Share a guide or use case for this OSS in Markdown. Articles are published after administrator approval.

Explore next

• Elysia19,216 Stars

  1 shared tag(s) · 1 shared category(s) · Same language

  build TypeScript web APIs around Bun with end-to-end type safety, runtime validation, and Web Standard adapters

  TypeScript
• Apollo Server13,951 Stars

  1 shared tag(s) · 1 shared category(s) · Same language

  build Node.js GraphQL APIs from schemas and resolvers

  TypeScript
• Hoppscotch80,561 Stars

  2 shared tag(s) · 2 shared category(s) · Same language

  Span REST, GraphQL, realtime requests, and collection tests across web, desktop, CLI, and self-hosted API workflows

  TypeScript
• WireMock7,387 Stars

  2 shared tag(s) · 2 shared category(s)

  Virtualize HTTP APIs with request matching, dynamic responses, delays/faults, and record/playback in a mock server or library

  Java
• Insomnia40,036 Stars

  1 shared tag(s) · 2 shared category(s) · Same language

  combine API design, requests, testing, and CI workflows in a desktop client

  TypeScript
• Bruno47,337 Stars

  1 shared tag(s) · 2 shared category(s)

  manage API collections as local Bru files in Git and run them from desktop, CLI, or CI

  JavaScript