Nano ID
A tiny, secure, URL-friendly, unique string ID generator for JavaScript.
Safe. It uses cryptographically strong random APIs and tests distribution of symbols.
Small. 143 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_~
).
As result it could reduce ID size from 36 to 21 symbols.
var nanoid = require('nanoid')
model.id = nanoid() //=> "V1StGXR8_Z5jdHi6B~myT"
The generator supports Node.js, React Native, and [all browsers].
Security
See a good article about random generators theory: Secure random values (in Node.js)
Unpredictability
Instead of using the unsafe Math.random()
, Nano ID uses the crypto
module
in Node.js and the Web Crypto API in browsers. This modules use unpredictable
hardware random generator.
Uniformity
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.
Comparison with UUID
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 3 times less than
uuid/v4
package: 143 bytes instead of 435.
Benchmark
$ ./test/benchmark
nanoid 353,737 ops/sec
nanoid/non-secure 2,043,665 ops/sec
nanoid/generate 348,442 ops/sec
uuid/v4 350,075 ops/sec
shortid 85,107 ops/sec
Usage
Normal
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.
React Native and Web Workers
React Native and Web Worker don’t have access to secure random generator.
Security is important in ID, when ID should be unpredictable. For instance, in “access by URL” link generation.
If you don’t need unpredictable IDs, but you need React Native or Web Workers support, you can use non‑secure ID generator.
var nanoid = require('nanoid/non-secure')
model.id = nanoid() //=> "Uakgb_J5m9g~0JDMbcJqLJ"
Custom Alphabet or Length
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.
You can find popular alphabets in nanoid-dictionary
.
Alphabet must contain 256 symbols or less. Otherwise, the generator will not be secure.
Custom Random Bytes Generator
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
file.
var url = require('nanoid/url')
format(random, url, 10) //=> "93ce_Ltuub"
Tools
- ID size calculator to choice smaller ID size depends on your case.
nanoid-dictionary
with popular alphabets to use withnanoid/generate
.nanoid-cli
to generate ID from CLI.nanoid-good
to be sure that your ID doesn't contain any obscene words.
Other Programming Languages
Also, CLI tool is available to generate IDs from command line.