Side by side
Mock Service Worker vs WireMock
Both stand on api mocking tools. Which one you can start free with, which one lets you read the code, and what each costs once you pay.
Free plan Self-hostedWeb
MSW offers reusable request mocking across browser and Node.js contexts, with support for several API protocols and clients. Its interception approach has browser and Node.js boundaries, so check those limits against the requests your application makes.
Visit Mock Service Worker
Free plan APILinuxMac+3
WireMock Cloud supports a broad set of protocols and workflows, with local and CI/CD simulation options. Check the Free plan's call cap and the Enterprise quote-based pricing against your needs.
Visit WireMockThe facts
| Mock Service Worker | WireMock | |
|---|---|---|
| Free plan | Yes | Yes |
| Open source | Not published | Not published |
| Runs on | Self-hosted, Web | API, Linux, Mac, Self-hosted, Web, Windows |
| Lowest paid plan | Not published | Free or on request |
| Plans published | None | 2 |
| Maker | Not published | Not published |
| Website | mswjs.io | wiremock.io |
| On api mocking tools | #18 of 26 | #14 of 26 |
Mock Service Worker: what it does well
- Free and open source.
- Mocks HTTP, GraphQL, SSE and WebSocket APIs.
- Mock handlers can be reused across environments.
- Works with native fetch, Axios, React Query and Apollo.
What to know first
- Browser use requires serving a Service Worker script.
- Firefox page XMLHttpRequest requests are not reported to the worker.
- Direct net.connect() and net.createConnection() requests cannot be intercepted.
- Official Egghead courses require a paid subscription.
WireMock: what it does well
- Simulates five listed API protocols.
- Runner can record APIs and run simulations locally or in CI/CD.
- Imports mocks from common API and file formats.
- Remote MCP server and Agent Skills support named coding clients.
- Enterprise includes governance features and hybrid deployment.
What to know first
- Free is limited to one user and three mock APIs.
- Free includes only 1,000 API calls per month.
- Mocks stop running after the monthly quota is exceeded.
- Enterprise price is available only by tailored quote.
Alternatives to Mock Service Worker Alternatives to WireMock The whole list