Faker vs Prism

Free and open source

Free and open source

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

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

Everything, self-hosted

Everything, self-hosted

Category standard

OSS community · since 2010

Established

Stoplight (SmartBear) · since 2017

• Realistic, locale-aware data catches layout bugs that 'test test test' never will.
• Seedable, so generated data is reproducible when a test fails.
• Available in every major language with a similar API.

• 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.

• Generated data has no referential integrity or business rules — that is your job.
• Random data makes failures harder to reproduce unless you seed deliberately.
• Not a substitute for production-shaped data at realistic volume.

• 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.

Every project that needs fixtures more realistic than placeholder strings.

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