Mock Service Worker is an API mocking library for browser and Node.js that uses Service Workers to allow your requests to actually happen with no stubs, down to each tiniest request client detail, and intercept them at the network level.
π¬ Ask a questionπ Read the documentationπ Browse usage examplesπ Make your first contribution
Ecosystem
We favor composition in both how we write our code and how we distribute it. That's why instead of building a single monolithic package that's responsible for too many things, we distribute the core module with the essentials that everybody could use, and provide a set of standalone extensions that enable specific workflows and push the developer experience even further.
Native extensions
- @mswjs/data to model and query your mock data.
Third-party extensions
- msw-storybook-addon to write and test your Storybook stories.
Support us!
This project is the result of hundreds of hours of work that our contributors spend so that you could enjoy the best API mocking experience there is to offer. If you'd like us to bring new features and mitigate issues more effectively, consider supporting us.
By becoming a baker you help us ensure a bright future for the project. Remember that any contribution counts. Thank you.

Formed in 2009, the Archive Team (not to be confused with the archive.org Archive-It Team) is a rogue archivist collective dedicated to saving copies of rapidly dying or deleted websites for the sake of history and digital heritage. The group is 100% composed of volunteers and interested parties, and has expanded into a large amount of related projects for saving online and digital history.

