Nano ID

Very small secure URL-friendly unique ID generator.

var nanoid = require('nanoid')
model.id = nanoid() //=> "Uakgb_J5m9g~0JDMbcJqLJ"

Safe. It uses cryptographically-strong random APIs and tests symbols distribution.

Small. Only 258 bytes (minified and gzipped). Zero-dependency.

Compact. It uses more symbols than UUID (A-Za-z0-9_~) and have same uniqueness in 22 symbols instead of 36.

Generator supports Node.js and all browsers from IE 11.

Security

Good article about random generators theory: Secure random values (in Node.js)

Unpredictability

Nano ID doesn’t use unsafe Math.random(). It use crypto module in Node.js and Web Crypto API in browsers.

Uniformity

random % alphabet is a popular mistake in ID generator. Change to get some symbols will be lower and it will reduce amount of guesses in bruteforcing.

Nano ID use better algorithm and test uniformity:

Usage

Normal

Main module uses URL-friendly symbols (A-Za-z0-9_~) and return ID with 22 characters (to have same uniqueness as UUID).

var nanoid = require('nanoid')
model.id = nanoid() //=> "Uakgb_J5m9g~0JDMbcJqLJ"

Symbols -,.() are not encoded in URL, but in the end of link they could be detected as punctuation.

Custom Alphabet or Length

If you want to change ID alphabet or length you can use low-level generate module.

var generate = require('nanoid/generate')
model.id = generate('1234567890abcdef', 10) //=> "4f90d13a42"

If you want to use same URL-friendly symbols and just change length, you can get default alphabet from url module:

var url = require('nanoid/url')
model.id = generate(url, 10) //=> "Uakgb_J5m9"

Custom Random Bytes Generator

You can replace default safe random generators by format module. It could be useful if you need seed-based generator.

var format = require('nanoid/format')

function random (size) {
  var result = []
  for (var i = 0; i < size; i++) result.push(randomByte())
  return result
}

format(random, "abcdef", 10) //=> "fbaefaadeb"

random callback must accept array size and return array of random numbers.