Does this skill support the latest version of MSW?

Yes, this skill is specifically architected for MSW 2.x, utilizing modern APIs like HttpResponse and the http/graphql namespaces.

Can I use this for testing GraphQL APIs?

Absolutely. It includes patterns for mocking GraphQL queries and mutations, including handling variables and complex data structures.

How does it handle one-off test scenarios?

The skill promotes the use of server.use() to override global handlers at runtime, allowing you to customize responses for specific test cases.

Is it compatible with Vitest and Jest?

Yes, it provides standardized setup and teardown patterns that work seamlessly with Vitest, Jest, and other modern test runners.

MSW API Mocking

Name: MSW API Mocking
Author: yonatangross

byyonatangross

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Security & Testing

Intercepts and mocks network requests using Mock Service Worker 2.x to create deterministic frontend tests for REST, GraphQL, and WebSockets.

About

The MSW API Mocking skill provides a robust framework for network-level interception, allowing developers to simulate API responses without the brittle practice of mocking global fetch or axios modules. By leveraging MSW 2.x patterns, it enables production-grade testing of success states, complex error scenarios, and network latency. This skill is essential for frontend developers using React 19 or similar frameworks who need to verify UI behavior under various API conditions, including GraphQL mutations and real-time WebSocket events.

Key Features

Full support for MSW 2.x HTTP and GraphQL interceptors
29 GitHub stars
Network delay and latency simulation for testing loading states
Runtime handler overrides for test-specific response logic
WebSocket mocking for real-time event simulation
Native passthrough support for hybrid mocking environments

Use Cases

Simulating 500/404 errors to verify frontend error boundary behavior
Creating deterministic data responses for CI/CD integration tests
Mocking slow API endpoints to test and refine UI skeleton loaders

About

Key Features

Full support for MSW 2.x HTTP and GraphQL interceptors
29 GitHub stars
Network delay and latency simulation for testing loading states
Runtime handler overrides for test-specific response logic
WebSocket mocking for real-time event simulation
Native passthrough support for hybrid mocking environments

Use Cases

Simulating 500/404 errors to verify frontend error boundary behavior
Creating deterministic data responses for CI/CD integration tests
Mocking slow API endpoints to test and refine UI skeleton loaders