๐งฌ JSON Schema Data Generator
Supported types: string, int, float, bool, uuid, date, email
Result will appear here
Define a schema by listing one field per line as fieldName:type (e.g. id:uuid, name:string, age:int), choose how many records to generate, and get a pretty-printed JSON array of dummy data โ handy for mocking API responses or seeding test data. Supported types: string, int, float, bool, uuid, date, and email.
How to use
- In the "Schema" field, list one field per line as fieldName:type.
- Set how many records to generate.
- Click "Generate" to see a pretty-printed JSON array in the output box.
- Click "Copy" to copy the result to your clipboard.
How the calculation works
This tool reads a schema of "fieldName:type" lines, produces a random value of the right type for each, and generates a JSON array with the number of records you ask for. Values by type: string is one word from a short list of English words; int an integer from 0 to 1000; float a decimal from 0 to 1000 with two decimal places; bool true or false with equal probability; uuid a random UUID-format string; date a random ISO 8601 date-time within the past two years; email a random address at example.com. Lines that do not match the format, or name an unsupported type, are skipped and listed as warnings. Generation continues with the valid lines, so a mistake in part of the schema still gives you a result.
Worked example
Generating two records from this schema id:uuid name:string age:int active:bool One possible result [ {"id": "3f2aโฆ", "name": "river", "age": 482, "active": true}, {"id": "9c71โฆ", "name": "stone", "age": 57, "active": false} ] Values change every time you generate.
Things to be aware of
- Values are random placeholders and do not reproduce realistic distributions (such as plausible ages).
- The randomness is not cryptographically secure; do not use it for production IDs or tokens.
- Nested object and array types are not supported.
- Dates are generated relative to your device's current time.
FAQ
What types are supported?
string (a random short word), int (0-1000), float (0-1000 with 2 decimals), bool (true/false), uuid (a random UUID), date (a random ISO date within the last 2 years), and email (a random address at example.com).
What happens if a line is malformed?
Lines that don't match the fieldName:type format, or use an unsupported type, are skipped and listed as a warning below the schema โ the rest of the schema still generates normally.
Is this useful for mocking API responses?
Yes โ define a schema that mirrors your real API's field structure and use the output as mock data during frontend development.
Is there a limit on how many records I can generate?
It generates exactly as many records as you specify; requesting a very large number may take longer to process in your browser.
Can I define nested object schemas?
The current version only supports a flat list of fieldName:type pairs โ nested objects or array schemas aren't supported.