Mockaroo vs Prism
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
From $60 per year (indicative, Silver)
Free tierFree and open source
Open sourceWhat drives the bill
The metric that actually scales your invoice.
Cheap for what it does; higher tiers raise row limits and add API quota.
Free and open source. You pay in engineering time and CI minutes.
Free tier
Free for up to 1,000 rows per download and a limited number of saved schemas.
Everything, self-hosted
Open source
Apache-2.0
Self-hostable
No-code authoring
Languages
Platforms
Fits teams
Adoption
Established
Mockaroo LLC · since 2014
Established
Stoplight (SmartBear) · since 2017
Strengths
- No code required — an analyst or tester can design a dataset themselves.
- Very large library of realistic field types including regional formats.
- Formula fields allow simple business rules between columns.
- 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.
Limitations
- Referential integrity across related tables is limited.
- Free-tier row limits are low for realistic volume testing.
- Data is generated on a third-party service, which needs a privacy check for schema sensitivity.
- 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.
Best for
Quickly producing a realistic dataset for a demo, a load test or a new environment.
Design-first API teams who want mocks that are provably in sync with the contract.
Pricing last reviewed August 2026 and is indicative only — confirm on each vendor’s own page.