Free · Make usernames for form testing

Username Regex Sample Generator

Generate lowercase usernames that follow a clear length and character rule.

Real randexp.js generation
Private in your browser
Safe count and repeat caps

Generate usernames

Enter a pattern without / slash marks. Samples are generated locally with safe count and repeat caps.

Set the pattern22 / 400 characters

Regular expressionWrite the pattern only. Example: ^[A-Z]{3}-\d{4}$

FlagsOptional. Use each flag once.Number of samples1 to 250Open repeat capCaps * and + from 1 to 40.Seed (optional)The same seed repeats the set.

Private local generatorrandexp.js 0.5.3 · no upload

Use the samplesReady when you are

Your samples will appear here

Nothing is uploaded. A safety cap keeps open-ended repeats and large batches under control.

Three simple steps

How to use it

Adjust the username pattern if needed.
Generate a varied local list.
Test allowed characters and lengths.

Your pattern stays on this device

randexp.js makes every string inside this browser tab. Bookify does not upload or save the pattern, seed, or samples. Generation is capped, and random examples do not replace full validation tests.