A tiny, secure, URL-friendly, unique string ID generator for JavaScript.
var nanoid = require('nanoid')
model.id = nanoid() //=> "V1StGXR8_Z5jdHi6B~myT"
Safe. It uses cryptographically strong random APIs and guarantees a proper distribution of symbols.
Small. Only 162 bytes (minified and gzipped). No dependencies. It uses Size Limit to control size.
Compact. It uses a larger alphabet than UUID (A-Za-z0-9_~
)
and has a similar number of unique IDs in just 21 symbols instead of 36.
The generator supports Node.js and all browsers starting from IE 11.
See a good article about random generators theory: Secure random values (in Node.js)
Instead of using the unsafe Math.random()
, Nano ID uses the crypto
module
in Node.js and the Web Crypto API in browsers.
random % alphabet
is a popular mistake to make when coding an ID generator.
The spread will not be even; there will be a lower chance for some symbols
to appear compared to others—so it will reduce the number of tries
when brute-forcing.
Nano ID uses a better algorithm and is tested for uniformity:
Nano ID is quite comparable to UUID v4 (random-based). It has a similar number of random bits in the ID (126 in Nano ID and 122 in UUID), so it has a similar collision probability:
For there to be a one in a billion chance of duplication, 103 trillion version 4 IDs must be generated.
There are two main differences between Nano ID and UUID v4:
- Nano ID uses a bigger alphabet, so a similar number of random bits are packed in just 21 symbols instead of 36.
- Nano ID code is less than half the size of the
uuid/v4
package: 162 bytes instead of 435.
$ ./benchmark
nanoid 375,840 ops/sec
nanoid/generate 268,747 ops/sec
uuid/v4 374,767 ops/sec
shortid 41,260 ops/sec
The main module uses URL-friendly symbols (A-Za-z0-9_~
) and returns an ID
with 21 characters (to have a collision probability similar to UUID v4).
var nanoid = require('nanoid')
model.id = nanoid() //=> "Uakgb_J5m9g~0JDMbcJqLJ"
Symbols -,.()
are not encoded in the URL. If used at the end of a link
they could be identified as a punctuation symbol.
If you want to reduce ID length (and increase collisions probability), you can pass the length as an argument:
nanoid(10) //=> "IRFa~VaY2b"
Don’t forget to check safety of your ID length in our ID collision probability calculator.
If you want to change the ID's alphabet or length
you can use the low-level generate
module.
var generate = require('nanoid/generate')
model.id = generate('1234567890abcdef', 10) //=> "4f90d13a42"
Check safety of your custom alphabet and ID length in our ID collision probability calculator.
Alphabet must contain 256 symbols or less. Otherwise, the generator will not be secure.
You can replace the default safe random generator using the format
module.
For instance, to use a 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 the array size and return an array
with random numbers.
If you want to use the same URL-friendly symbols with format
,
you can get the default alphabet from the url
module:
var url = require('nanoid/url')
format(random, url, 10) //=> "93ce_Ltuub"
Also, CLI tool is available to generate IDs from command line.
- nanoid-dictionary — a set of predefined strings to use with nanoid generator