unique-username-generator

A tiny, flexible username generator for Node and browsers. Generate from email or dictionaries; control separator, style, max length, optional digits, profanity filtering, templates, deterministic seeds, and batch generation.

Security note: this library generates human-friendly display names. It is not intended for security-sensitive randomness (e.g., passwords, tokens). It prefers Web Crypto when available and falls back to a non-crypto PRNG only as a last resort.

Installation

npm install unique-username-generator --save

Importing

// Using Node.js `require()`
const { generateFromEmail, generateUsername } = require("unique-username-generator");
// Using ES6 imports
import { generateFromEmail, generateUsername } from "unique-username-generator";

Usage

Generate username from email

It will generate username from email and add upto six random digits at the end of the name.

// Simple: add three random digits
generateFromEmail("lakshmi.narayan@example.com", 3); // "lakshminarayan234"

// Advanced: options
generateFromEmail("123john@example.com", { randomDigits: 2, stripLeadingDigits: true }); // "john12"
generateFromEmail("12345@example.com", { randomDigits: 0, leadingFallback: "member" });  // "member"

Randomly generate unique username.

It will generate unique username from adjectives, nouns, random digits and separator. You can control these following parameters - separator, number of random digits and maximum length of a username.

// generaterUsername(separator, number of random digits, maximum length)

// Without any parameter
const username = generateUsername();
console.log(username); // blossomlogistical

// With any separator like "-, _"
const username = generateUsername("-");
console.log(username); // blossom-logistical

// With random digits and no separator
const username = generateUsername("", 3);
console.log(username); // blossomlogistical732

// With maximum length constraint and no separator, no random digits
const username = generateUsername("", 0, 15);
console.log(username); // blossomlogistic

// With maximum length constraint and separator but no random digits
const username = generateUsername("-", 0, 15);
console.log(username); // blossom-logisti

// With maximum length constraint and random digits but no separator
const username = generateUsername("", 2, 19);
console.log(username); // blossomlogistical73

// With all parameters
const username = generateUsername("-", 2, 20, "unique username");
console.log(username); // unique-username-73

Default dictionaries

By default, the unique username generator library comes with 2 dictionaries out of the box, so that you can use them straight away.

The new syntax for using the default dictionaries is the following:

import { uniqueUsernameGenerator, Config, adjectives, nouns } from 'unique-username-generator';

const config: Config = {
  dictionaries: [adjectives, nouns]
}

const username: string = uniqueUsernameGenerator(config); // blossomlogistical

Custom dictionaries

You might want to provide your custom dictionaries to use for generating your unique username, in order to meet your project requirements. You can easily do that using the dictionaries option.

import { uniqueUsernameGenerator } from 'unique-username-generator';

const marvelCharacters = [
  'Iron Man',
  'Doctor Strange',
  'Hulk',
  'Captain America',
  'Thanos'
];

const config: Config = {
  dictionaries: [marvelCharacters],
  separator: '',
  style: 'capital',
  randomDigits: 3
}

const username: string = uniqueUsernameGenerator(config); // Hulk123

Profanity filtering and exclusions

By default, the generator filters out common profane words from the built-in dictionaries to avoid unsafe names. You can extend or override the blocklist using exclude and profanityList.

import { uniqueUsernameGenerator, adjectives, nouns, DEFAULT_PROFANITY } from 'unique-username-generator';

const username = uniqueUsernameGenerator({
  dictionaries: [adjectives, nouns],
  exclude: ['beta', 'foo'],            // custom exclusions
  profanityList: DEFAULT_PROFANITY,    // extend/override blocklist
  randomDigits: 0
});

Output styles

Additional styles are supported beyond lowerCase, upperCase, and capital:

camelCase
pascalCase
kebabCase
snakeCase
titleCase (capitalize each word)

uniqueUsernameGenerator({ dictionaries: [["blue"],["whale"]], separator: "-", style: 'camelCase', randomDigits: 0 }); // blueWhale

Templates and deterministic output

// Template tokens: {adjective}, {noun}, positional {0},{1},... and {digits:n}
uniqueUsernameGenerator({
  dictionaries: [adjectives, nouns],
  template: "{adjective}-{noun}-{digits:2}",
  seed: "v1",           // make output deterministic
  style: "lowerCase",
}); // e.g. "brave-otter-42"

Batch generation

import { generateMany, generateUniqueAsync } from 'unique-username-generator';

// Generate N (optionally unique) usernames in-memory
const many = generateMany({ dictionaries: [adjectives, nouns], count: 5, unique: true });

// Generate a username that is unique against an external store
const taken = new Set(["cool-fox"]);
const username = await generateUniqueAsync(
  { dictionaries: [adjectives, nouns], separator: "-" },
  (candidate) => taken.has(candidate)
);

CLI

After installing, a simple CLI is available as usergen (aliases: usernamegen, unique-username, uuname).

Usage: usergen [options]

Options:
  -s, --separator <sep>     Separator between words (default: empty)
  -d, --digits <n>          Number of random digits to append (0-6)
  -l, --length <n>          Maximum username length (default: 15)
      --style <style>       Style: lowerCase | upperCase | capital | camelCase | pascalCase | kebabCase | snakeCase | titleCase
  -U, --upper               Shortcut for --style upperCase
      --seed <seed>         Deterministic seed for reproducible output
  -t, --template <tpl>      Template, e.g. "{adjective}-{noun}-{digits:2}"
  -c, --count <n>           Generate many
  -u, --unique              Ensure unique usernames within this run
  -o, --out <file>          Write results to a file (UTF-8)
      --unsafe              Disable profanity filtering
  -U, --upper               Shortcut for --style upperCase
  -D, --dict <a,b,c>        Provide a custom dictionary (can be used multiple times)
  -x, --exclude <a,b,c>     Extra words to exclude
  -h, --help                Show help

API