mswjs

mswjs/msw

Industry standard API mocking for JavaScript.

9 good first / help-wanted issues · TypeScript · last activity Aug 25, 2026

api api-mocking devtools mock mock-service-worker mocking mocking-framework mocking-library msw mswjs service-worker
9 Open Issues Need Help Last updated: Aug 25, 2026

Open Issues Need Help

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help wanted feature needs:discussion
mswjs/msw
18.2K

Industry standard API mocking for JavaScript.

TypeScript
#api#api-mocking#devtools#mock#mock-service-worker#mocking#mocking-framework#mocking-library#msw#mswjs#service-worker
bug help wanted good first issue scope:node
mswjs/msw
18.2K

Industry standard API mocking for JavaScript.

TypeScript
#api#api-mocking#devtools#mock#mock-service-worker#mocking#mocking-framework#mocking-library#msw#mswjs#service-worker
good first issue
mswjs/msw
18.2K

Industry standard API mocking for JavaScript.

TypeScript
#api#api-mocking#devtools#mock#mock-service-worker#mocking#mocking-framework#mocking-library#msw#mswjs#service-worker

AI Summary: This GitHub issue reports a bug in MSW where unhandled errors thrown within a WebSocket `connection` event listener are not propagated to the client-side `WebSocket.onerror` event. This prevents users from effectively testing error handling scenarios for WebSocket connections mocked by MSW. A reproduction repository and code snippet are provided to demonstrate the issue.

Complexity: 3/5
bug good first issue api:ws
mswjs/msw
18.2K

Industry standard API mocking for JavaScript.

TypeScript
#api#api-mocking#devtools#mock#mock-service-worker#mocking#mocking-framework#mocking-library#msw#mswjs#service-worker
mswjs/msw
18.2K

Industry standard API mocking for JavaScript.

TypeScript
#api#api-mocking#devtools#mock#mock-service-worker#mocking#mocking-framework#mocking-library#msw#mswjs#service-worker
bug good first issue scope:node
mswjs/msw
18.2K

Industry standard API mocking for JavaScript.

TypeScript
#api#api-mocking#devtools#mock#mock-service-worker#mocking#mocking-framework#mocking-library#msw#mswjs#service-worker
good first issue
mswjs/msw
18.2K

Industry standard API mocking for JavaScript.

TypeScript
#api#api-mocking#devtools#mock#mock-service-worker#mocking#mocking-framework#mocking-library#msw#mswjs#service-worker

AI Summary: This GitHub issue reports an intermittent bug where requests made immediately after calling `stop` on the Mock Service Worker (MSW) service worker do not always pass through properly. Users observe that a second image sometimes fails to load (either pending or improperly served) in Chromium-based browsers and Safari, particularly after multiple page reloads, suggesting a race condition during service worker unregistration.

Complexity: 4/5
bug help wanted scope:browser needs:triage
mswjs/msw
18.2K

Industry standard API mocking for JavaScript.

TypeScript
#api#api-mocking#devtools#mock#mock-service-worker#mocking#mocking-framework#mocking-library#msw#mswjs#service-worker

AI Summary: This task involves enhancing the Mock Service Worker (MSW) library by publicly exposing selected internal utilities and TypeScript types. This will improve the library's extensibility, allowing advanced users to create custom handlers and integrations more easily and safely, without relying on potentially unstable internal imports. The task includes identifying suitable internal functions and types for exposure, deciding on the optimal export structure, updating documentation, and creating a pull request.

Complexity: 4/5
help wanted feature DX
mswjs/msw
18.2K

Industry standard API mocking for JavaScript.

TypeScript
#api#api-mocking#devtools#mock#mock-service-worker#mocking#mocking-framework#mocking-library#msw#mswjs#service-worker