Mock Service Worker vs Mockaroo

Free and open source

From $60 per year (indicative, Silver)

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

Cheap for what it does; higher tiers raise row limits and add API quota.

Everything, self-hosted

Free for up to 1,000 rows per download and a limited number of saved schemas.

Category standard

OSS community · since 2020

Established

Mockaroo LLC · since 2014

• 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.

• 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.

• JavaScript ecosystem only.
• Service Worker registration adds a setup step and occasional caching confusion.
• Handlers can drift from the real API without contract verification.

• 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.

Front-end teams that want one mocking approach across every kind of test.

Quickly producing a realistic dataset for a demo, a load test or a new environment.