How to generate reproducible JSON and CSV test data
Define one field:type per line and generate up to 5000 fake records. Choose English or Chinese data, an integer seed, and JSON or CSV output. The same settings repeat the same data within the pinned Faker version. No account or API key is needed.
How do you do it?
- Define 1–30 unique field:type lines, for example id:uuid and name:fullName.
- Choose a count of 1–5000, an integer seed, data language, and output format.
- Select Run, inspect the generated records, and download JSON or CSV.
Generate typed boolean test records
Boolean fields remain JSON booleans. The adopted Faker version and seed determine the sequence; check actual output when changing versions.
Input:
Fields: active:boolean
Count: 3; seed: 42; language: English
Output:
[
{"active": true},
{"active": false},
{"active": false}
]When is this workflow useful?
Use this tool to create reproducible fixtures and sample tables. Use the existing UUID or Password Generator for cryptographic randomness; use an API schema to define production constraints.
What should you check before relying on the result?
Generated values are synthetic test data and do not establish valid identities or deliverable email addresses. Integer fields range from 0 to 100. CSV converts cells to text and prefixes formula-like strings with an apostrophe; review imports in the target spreadsheet. Do not use seeded UUIDs as production secrets.
What can go wrong?
| Problem | What to try |
|---|---|
| A field definition is rejected. | The type is unsupported, a field name repeats, or the name is reserved. Use unique field names and uuid, fullName, email, integer, boolean, company, or word. |
| A saved seed produces different results later. | The locale, field order, generation settings, or library version changed. Keep all settings and the pinned Faker version together with the fixture. |
Frequently asked questions
Do I need to upload data or sign in?
No. Processing runs in the current browser. This site serves the page and required static engine assets.
Why does the result disappear after I edit the input?
The tool clears stale output so a previous result cannot be mistaken for the new one. Run again after changing input or settings.
References
First edition: steps checked against the current tool interface, with examples and known limits.