JSON-Utils

JSON Mock Data Generator

Generate sample JSON from a JSON Schema for tests, fixtures, and demos. The generator honors enums, defaults, examples, common string formats, and numeric bounds, and it is deterministic, so the same schema always yields the same sample. Keywords it cannot honor are listed as warnings.

JSON Schema
Sample data
Result will appear here
Ready. Press Generate data or Ctrl+Enter.

How to use the JSON Mock Data Generator

  1. Paste a JSON Schema.
  2. Press Generate.
  3. Copy the sample document into your tests.

Example

Format hints produce plausible values, not random strings.

{"type":"object","properties":{"email":{"type":"string","format":"email"},"age":{"type":"integer","minimum":18}}}

Frequently asked questions

Is the output random?

No, it is deterministic on purpose, so test fixtures stay stable between runs.

Does it support oneOf and anyOf?

It picks the first branch and tells you in a warning, rather than silently inventing data.