Generate mock data from JSON Schema

Generate repeatable mock JSON from a JSON Schema for tests and prototypes.

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ToolJSON Schema Faker
Input
Output
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Preview

How it works

The schema is traversed to create primitive values, properties, arrays, enums, and selected format examples. A seeded random generator repeats the same sample while unseeded runs vary.

  • One object and a fixed seed make previews reproducible.
  • Format examples are test data, not domain validation.

Worked example

Generate User Data
Generate a fake user object from a JSON Schema definition
Input
											{
  "type": "object",
  "properties": {
    "name": {"type": "string"},
    "email": {"type": "string", "format": "email"},
    "age": {"type": "integer", "minimum": 18, "maximum": 65}
  },
  "required": ["name", "email", "age"]
}
Output
												{
  "name": "xcbiuyz",
  "email": "[email protected]",
  "age": 23
}

When to use this

API fixtures, mock servers, and load-test payloads generate schema-shaped data.

Edge cases

  • An unresolved $ref may leave a referenced branch incomplete.
  • Numeric minimum and maximum can force an edge value.
  • A required property without a type receives a generic value.

References