Mock Service Worker vs WireMock
Feature checklists rarely decide anything. What decides it is the pricing metric, who has to write the tests, and which limitation you can live with.
Entry price
Free and open source
Open sourceFree tier available
Free tierWhat drives the bill
The metric that actually scales your invoice.
Free and open source. You pay in engineering time and CI minutes.
Open source is free; WireMock Cloud is a paid hosted service for shared team mocks.
Free tier
Everything, self-hosted
Open-source WireMock is complete and free.
Open source
MIT
Apache-2.0
Self-hostable
No-code authoring
Languages
Platforms
Fits teams
Adoption
Category standard
OSS community · since 2020
Category standard
WireMock Inc. · since 2013
Strengths
- One set of handlers reused across unit, component, E2E and local development.
- Application code is completely unaware it is being mocked — no test-only branches.
- Supports REST and GraphQL with the same model.
- Fault and latency injection lets you test the error paths that never occur on demand in a real sandbox.
- Record-and-replay produces a realistic mock from live traffic quickly.
- Runs anywhere: embedded, standalone, container or cloud.
Limitations
- JavaScript ecosystem only.
- Service Worker registration adds a setup step and occasional caching confusion.
- Handlers can drift from the real API without contract verification.
- Recorded stubs drift from the real service unless you re-record or verify contracts.
- Complex stateful scenarios get verbose in JSON.
- HTTP only — not for message queues or gRPC without extensions.
Best for
Front-end teams that want one mocking approach across every kind of test.
Teams whose integration tests depend on third-party HTTP services.
Pricing last reviewed August 2026 and is indicative only — confirm on each vendor’s own page.