What this tool does
Paste, upload, or load an example OpenAPI/Swagger document and get realistic mock response data for every endpoint — useful for building a frontend before the real API exists, or for writing tests that don't depend on a live backend. Browse mocks per endpoint, or export everything at once as a JSON file or as ready-to-use Mock Service Worker handlers.
How example values are generated
- Explicit values first. If a schema has its own
example,default, orenumlist, that's used before anything is made up. - Format-aware strings.
format: email,uuid,date,date-time, anduriall produce values that actually look like their format, not a generic placeholder. - Randomize values. Off by default behavior is a single deterministic placeholder per type; turning this on generates varied values instead — including incrementing
idfields across array items, so a list of 5 items looks like 5 different records rather than 5 copies of the same one. - Array items. Controls how many items array responses generate, from 1 to 10.
Exporting mocks
All mocks (.json) downloads every response across every endpoint as one file, keyed by method, path, and status — useful as a reference or for feeding into other tooling. MSW handlers (.js) generates a ready-to-import handlers.js file using MSW's http/HttpResponse API, with one handler per endpoint using its primary (first 2xx, or first available) response.
FAQ
Does this run an actual mock server?
No — everything here is static generated data and code you export and use in your own project (with MSW, json-server, or however you already mock APIs). Nothing is hosted.
My spec looks fine but the mocks seem off
Run it through the OpenAPI Validator first — a broken $ref or malformed response schema can produce an incomplete mock without showing up as a parse error.
Is my spec uploaded anywhere?
No — generation happens entirely in your browser. Nothing is sent to a server.