Mock Dream vs MSW (Mock Service Worker)
Service-worker mocking library · free Chrome alternative
MSW is a JavaScript library that registers a service worker to intercept requests during dev and tests.
Where MSW (Mock Service Worker) wins
Code-first, version-controlled, runs in Node and the browser, great for Jest/Vitest.
Where Mock Dream wins
Mock Dream is for ad-hoc debugging on any site — including production pages and apps you don't own. No code changes, no service-worker registration.
Side-by-side
| Feature | MSW (Mock Service Worker) | Mock Dream |
|---|---|---|
| Pricing | Free, MIT | Free forever |
| Sign-up required | No | Never |
| Runs a server | Service worker (in your app) | No — runs in your tab |
| Mocks fetch + XHR | Both (via SW) | Both, from one rule |
| Per-rule CORS | Bypassed by SW | One toggle |
| Live traffic console | Devtools network | Built-in, filterable |
| Themes | 1 (default) | 6 manga themes |
| Install size | npm package + setup file | <300 KB extension |
FAQ
- Is Mock Dream really a free MSW (Mock Service Worker) alternative?
- Yes. Mock Dream is MIT-licensed, has zero paid tier, no telemetry, and stores everything locally in
chrome.storage.local. - Can it replace MSW (Mock Service Worker) for my workflow?
- If your job is "intercept fetch/XHR in a browser tab and return mock JSON", yes. If you need code-first, version-controlled, runs in node and the browser, great for jest/vitest., keep MSW (Mock Service Worker) — Mock Dream and MSW (Mock Service Worker) can coexist on the same machine.
- Does Mock Dream work on Edge, Brave, Opera or Arc?
- Yes — any Chromium browser running Manifest V3 (Chrome 116+).
Try Mock Dream — no install, no sign-up
popup runs the same engine as the extension