Mockoon vs Prism

From $9 per user/month (indicative, Cloud)

Free and open source

Free locally; the paid cloud tier adds hosted mocks and team sync.

Free and open source. You pay in engineering time and CI minutes.

The desktop app and CLI are free and open source.

Everything, self-hosted

Widely used

Mockoon · since 2017

Established

Stoplight (SmartBear) · since 2017

• Genuinely a minute from download to a working mock API.
• Dynamic templating with faker-style helpers produces realistic responses.
• Proxy mode mocks only the routes you need and passes the rest through.

• The mock is generated from the spec, so it cannot silently diverge from the contract.
• Validation proxy mode checks that a real implementation matches its own spec.
• Zero configuration beyond having an OpenAPI file.

• Desktop-first; sharing mocks across a team needs the paid cloud or a committed config file.
• HTTP only.
• Less suited to complex stateful behaviour than WireMock.

• Useless without an accurate OpenAPI document.
• Limited stateful behaviour — it is spec-driven, not scenario-driven.
• Generated example data is uninteresting unless examples are in the spec.

Front-end developers unblocking themselves while a backend is still being built.

Design-first API teams who want mocks that are provably in sync with the contract.