RandJoy
Mock data generator
Make small, explicit fixtures for forms, tables and import pipelines.
Latest result
Ready when you are
Make small, explicit fixtures for forms, tables and import pipelines.How it works
- Start with the example schema, or edit its typed columns in Settings. Give every column a distinct name.
- Choose the row count and seed, then generate. Check the first 20 rows in the preview before exporting.
- Choose CSV, JSON or JSONL for all rows. Export the recipe to keep the schema and settings alongside the data.
Fictional fixtures with declared types
IDs count from 1. Integer bounds are inclusive; decimals sample the interval before rounding to six places. Boolean columns use your chosen probability. Categories choose from the supplied values, including repeated values if listed. Dates cover the 366 calendar days of 2024. Emails use [email protected] and subsequent row numbers; they are reserved examples. Columns are generated independently, without business relationships or population realism.
Your inputs stay with you
Your inputs and generated results stay in this browser. Settings and five recent runs use local storage; clearing browser data removes them. Export a copy to keep it. Hosting may record standard page-request logs, but generated rows and participant names are not sent to the server.
How are nulls and text exported?
JSON and JSONL preserve typed numbers, booleans and nulls. CSV quotes every cell, doubles embedded quotes and represents null as an empty field. Category text is exported as supplied; spreadsheet programs may interpret formula-like text when opening CSV. Use JSON for exact typed inspection. Exported files contain data only; the recipe is separate.
Repeatable test data
The research tools use the versioned xoshiro128** pseudorandom generator with named seed streams. They are intended for small examples and testing, not secrets or certified draws. A recipe records parameters and generator version. Floating-point transforms are rounded to six decimal places; keep exported files when exact cross-platform bytes matter.
Seeds are repeatable. Use the password generator for credentials.