uuid

For the creation of RFC9562 (formally RFC4122) UUIDs

Complete - Support for all RFC9562 UUID versions
Cross-platform - Support for ...
- CommonJS, ECMAScript Modules
- NodeJS 16+ (LTS releases)
- Chrome, Safari, Firefox, Edge browsers
- React Native / Expo
Secure - Cryptographically-strong random values
Compact - No dependencies, tree-shakable
CLI - Includes the uuid command line utility
Typescript - Types now included

Note

w> uuid@11 is now available: See the CHANGELOG for details. TL;DR:

TypeScript support is now included (remove @types/uuid from your dependencies)
Subtle changes to how the options arg is interpreted for v1(), v6(), and v7(). See details
Binary UUIDs are now Uint8Arrays. (May impact callers of parse(), stringify(), or that pass an option#buf argument to v1()-v7().)

Quickstart

1. Install

npm install uuid

2. Create a UUID

ESM-syntax (must use named exports):

import { v4 as uuidv4 } from 'uuid';
uuidv4(); // ⇨ '9b1deb4d-3b7d-4bad-9bdd-2b0d7b3dcb6d'

... CommonJS:

const { v4: uuidv4 } = require('uuid');
uuidv4(); // ⇨ '1b9d6bcd-bbfd-4b2d-9b5d-ab8dfbbd4bed'

For timestamp UUIDs, namespace UUIDs, and other options read on ...

API Summary


`uuid.NIL`	The nil UUID string (all zeros)	New in `uuid@8.3`
`uuid.MAX`	The max UUID string (all ones)	New in `uuid@9.1`
`uuid.parse()`	Convert UUID string to array of bytes	New in `uuid@8.3`
`uuid.stringify()`	Convert array of bytes to UUID string	New in `uuid@8.3`
`uuid.v1()`	Create a version 1 (timestamp) UUID
`uuid.v1ToV6()`	Create a version 6 UUID from a version 1 UUID	New in `uuid@10`
`uuid.v3()`	Create a version 3 (namespace w/ MD5) UUID
`uuid.v4()`	Create a version 4 (random) UUID
`uuid.v5()`	Create a version 5 (namespace w/ SHA-1) UUID
`uuid.v6()`	Create a version 6 (timestamp, reordered) UUID	New in `uuid@10`
`uuid.v6ToV1()`	Create a version 1 UUID from a version 6 UUID	New in `uuid@10`
`uuid.v7()`	Create a version 7 (Unix Epoch time-based) UUID	New in `uuid@10`
~~`uuid.v8()`~~	"Intentionally left blank"
`uuid.validate()`	Test a string to see if it is a valid UUID	New in `uuid@8.3`
`uuid.version()`	Detect RFC version of a UUID	New in `uuid@8.3`

API

uuid.NIL

The nil UUID string (all zeros).

Example:

import { NIL as NIL_UUID } from 'uuid';

NIL_UUID; // ⇨ '00000000-0000-0000-0000-000000000000'

uuid.MAX

The max UUID string (all ones).

Example:

import { MAX as MAX_UUID } from 'uuid';

MAX_UUID; // ⇨ 'ffffffff-ffff-ffff-ffff-ffffffffffff'

uuid.parse(str)

Convert UUID string to array of bytes


`str`	A valid UUID `String`
returns	`Uint8Array[16]`
throws	`TypeError` if `str` is not a valid UUID

Note

Ordering of values in the byte arrays used by parse() and stringify() follows the left ↠ right order of hex-pairs in UUID strings. As shown in the example below.

Example:

import { parse as uuidParse } from 'uuid';

// Parse a UUID
uuidParse('6ec0bd7f-11c0-43da-975e-2a8ad9ebae0b'); // ⇨ 
  // Uint8Array(16) [
  //   110, 192, 189, 127,  17,
  //   192,  67, 218, 151,  94,
  //    42, 138, 217, 235, 174,
  //    11
  // ]

uuid.stringify(arr[, offset])

Convert array of bytes to UUID string


`arr`	`Array`-like collection of 16 values (starting from `offset`) between 0-255.
[`offset` = 0]	`Number` Starting index in the Array
returns	`String`
throws	`TypeError` if a valid UUID string cannot be generated

Note

Ordering of values in the byte arrays used by parse() and stringify() follows the left ↠ right order of hex-pairs in UUID strings. As shown in the example below.

Example:

import { stringify as uuidStringify } from 'uuid';

const uuidBytes = Uint8Array.of(
  0x6e,
  0xc0,
  0xbd,
  0x7f,
  0x11,
  0xc0,
  0x43,
  0xda,
  0x97,
  0x5e,
  0x2a,
  0x8a,
  0xd9,
  0xeb,
  0xae,
  0x0b
);

uuidStringify(uuidBytes); // ⇨ '6ec0bd7f-11c0-43da-975e-2a8ad9ebae0b'

uuid.v1([options[, buffer[, offset]]])

Create an RFC version 1 (timestamp) UUID


[`options`]	`Object` with one or more of the following properties:
[`options.node = (random)` ]	RFC "node" field as an `Array[6]` of byte values (per 4.1.6)
[`options.clockseq = (random)`]	RFC "clock sequence" as a `Number` between 0 - 0x3fff
[`options.msecs = (current time)`]	RFC "timestamp" field (`Number` of milliseconds, unix epoch)
[`options.nsecs = 0`]	RFC "timestamp" field (`Number` of nanoseconds to add to `msecs`, should be 0-10,000)
[`options.random = (random)`]	`Array` of 16 random bytes (0-255) used to generate other fields, above
[`options.rng`]	Alternative to `options.random`, a `Function` that returns an `Array` of 16 random bytes (0-255)
[`buffer`]	`Array \| Buffer` If specified, uuid will be written here in byte-form, starting at `offset`
[`offset` = 0]	`Number` Index to start writing UUID bytes in `buffer`
returns	UUID `String` if no `buffer` is specified, otherwise returns `buffer`
throws	`Error` if more than 10M UUIDs/sec are requested

Note

The default node id (the last 12 digits in the UUID) is generated once, randomly, on process startup, and then remains unchanged for the duration of the process.

Note

options.random and options.rng are only meaningful on the very first call to v1(), where they may be passed to initialize the internal node and clockseq fields.

Example:

import { v1 as uuidv1 } from 'uuid';

uuidv1(); // ⇨ '2c5ea4c0-4067-11e9-9bdd-2b0d7b3dcb6d'

Example using options:

import { v1 as uuidv1 } from 'uuid';

const options = {
  node: Uint8Array.of(0x01, 0x23, 0x45, 0x67, 0x89, 0xab),
  clockseq: 0x1234,
  msecs: new Date('2011-11-01').getTime(),
  nsecs: 5678,
};
uuidv1(options); // ⇨ '710b962e-041c-11e1-9234-0123456789ab'

uuid.v1ToV6(uuid)

Convert a UUID from version 1 to version 6

import { v1ToV6 } from 'uuid';

v1ToV6('92f62d9e-22c4-11ef-97e9-325096b39f47'); // ⇨ '1ef22c49-2f62-6d9e-97e9-325096b39f47'

uuid.v3(name, namespace[, buffer[, offset]])

Create an RFC version 3 (namespace w/ MD5) UUID

API is identical to v5(), but uses "v3" instead.

Important

Per the RFC, "If backward compatibility is not an issue, SHA-1 [Version 5] is preferred."

uuid.v4([options[, buffer[, offset]]])

Create an RFC version 4 (random) UUID


[`options`]	`Object` with one or more of the following properties:
[`options.random`]	`Array` of 16 random bytes (0-255)
[`options.rng`]	Alternative to `options.random`, a `Function` that returns an `Array` of 16 random bytes (0-255)
[`buffer`]	`Array \| Buffer` If specified, uuid will be written here in byte-form, starting at `offset`
[`offset` = 0]	`Number` Index to start writing UUID bytes in `buffer`
returns	UUID `String` if no `buffer` is specified, otherwise returns `buffer`

Example:

import { v4 as uuidv4 } from 'uuid';

uuidv4(); // ⇨ '9b1deb4d-3b7d-4bad-9bdd-2b0d7b3dcb6d'

Example using predefined random values:

import { v4 as uuidv4 } from 'uuid';

const v4options = {
  random: Uint8Array.of(
    0x10,
    0x91,
    0x56,
    0xbe,
    0xc4,
    0xfb,
    0xc1,
    0xea,
    0x71,
    0xb4,
    0xef,
    0xe1,
    0x67,
    0x1c,
    0x58,
    0x36
  ),
};
uuidv4(v4options); // ⇨ '109156be-c4fb-41ea-b1b4-efe1671c5836'

uuid.v5(name, namespace[, buffer[, offset]])

Create an RFC version 5 (namespace w/ SHA-1) UUID


`name`	`String \| Array`
`namespace`	`String \| Array[16]` Namespace UUID
[`buffer`]	`Array \| Buffer` If specified, uuid will be written here in byte-form, starting at `offset`
[`offset` = 0]	`Number` Index to start writing UUID bytes in `buffer`
returns	UUID `String` if no `buffer` is specified, otherwise returns `buffer`

Note

The RFC DNS and URL namespaces are available as v5.DNS and v5.URL.

Example with custom namespace:

import { v5 as uuidv5 } from 'uuid';

// Define a custom namespace.  Readers, create your own using something like
// https://www.uuidgenerator.net/
const MY_NAMESPACE = '1b671a64-40d5-491e-99b0-da01ff1f3341';

uuidv5('Hello, World!', MY_NAMESPACE); // ⇨ '630eb68f-e0fa-5ecc-887a-7c7a62614681'

Example with RFC URL namespace:

import { v5 as uuidv5 } from 'uuid';

uuidv5('https://www.w3.org/', uuidv5.URL); // ⇨ 'c106a26a-21bb-5538-8bf2-57095d1976c1'

uuid.v6([options[, buffer[, offset]]])

Create an RFC version 6 (timestamp, reordered) UUID

This method takes the same arguments as uuid.v1().

import { v6 as uuidv6 } from 'uuid';

uuidv6(); // ⇨ '1e940672-c5ea-64c0-9b5d-ab8dfbbd4bed'

Example using options:

import { v6 as uuidv6 } from 'uuid';

const options = {
  node: [0x01, 0x23, 0x45, 0x67, 0x89, 0xab],
  clockseq: 0x1234,
  msecs: new Date('2011-11-01').getTime(),
  nsecs: 5678,
};
uuidv6(options); // ⇨ '1e1041c7-10b9-662e-9234-0123456789ab'

uuid.v6ToV1(uuid)

Convert a UUID from version 6 to version 1

import { v6ToV1 } from 'uuid';

v6ToV1('1ef22c49-2f62-6d9e-97e9-325096b39f47'); // ⇨ '92f62d9e-22c4-11ef-97e9-325096b39f47'

uuid.v7([options[, buffer[, offset]]])

Create an RFC version 7 (random) UUID


[`options`]	`Object` with one or more of the following properties:
[`options.msecs = (current time)`]	RFC "timestamp" field (`Number` of milliseconds, unix epoch)
[`options.random = (random)`]	`Array` of 16 random bytes (0-255) used to generate other fields, above
[`options.rng`]	Alternative to `options.random`, a `Function` that returns an `Array` of 16 random bytes (0-255)
[`options.seq = (random)`]	32-bit sequence `Number` between 0 - 0xffffffff. This may be provided to help insure uniqueness for UUIDs generated within the same millisecond time interval. Default = random value.
[`buffer`]	`Array \| Buffer` If specified, uuid will be written here in byte-form, starting at `offset`
[`offset` = 0]	`Number` Index to start writing UUID bytes in `buffer`
returns	UUID `String` if no `buffer` is specified, otherwise returns `buffer`

Example:

import { v7 as uuidv7 } from 'uuid';

uuidv7(); // ⇨ '01695553-c90c-705a-b56d-778dfbbd4bed'

uuid.v8()

"Intentionally left blank"

Note

Version 8 (experimental) UUIDs are "for experimental or vendor-specific use cases". The RFC does not define a creation algorithm for them, which is why this package does not offer a v8() method. The validate() and version() methods do work with such UUIDs, however.

uuid.validate(str)

Test a string to see if it is a valid UUID


`str`	`String` to validate
returns	`true` if string is a valid UUID, `false` otherwise

Example:

import { validate as uuidValidate } from 'uuid';

uuidValidate('not a UUID'); // ⇨ false
uuidValidate('6ec0bd7f-11c0-43da-975e-2a8ad9ebae0b'); // ⇨ true

Using validate and version together it is possible to do per-version validation, e.g. validate for only v4 UUIds.

import { version as uuidVersion } from 'uuid';
import { validate as uuidValidate } from 'uuid';

function uuidValidateV4(uuid) {
  return uuidValidate(uuid) && uuidVersion(uuid) === 4;
}

const v1Uuid = 'd9428888-122b-11e1-b85c-61cd3cbb3210';
const v4Uuid = '109156be-c4fb-41ea-b1b4-efe1671c5836';

uuidValidateV4(v4Uuid); // ⇨ true
uuidValidateV4(v1Uuid); // ⇨ false

uuid.version(str)

Detect RFC version of a UUID


`str`	A valid UUID `String`
returns	`Number` The RFC version of the UUID
throws	`TypeError` if `str` is not a valid UUID

Example:

import { version as uuidVersion } from 'uuid';

uuidVersion('45637ec4-c85f-11ea-87d0-0242ac130003'); // ⇨ 1
uuidVersion('6ec0bd7f-11c0-43da-975e-2a8ad9ebae0b'); // ⇨ 4

Note

This method returns 0 for the NIL UUID, and 15 for the MAX UUID.

Command Line

UUIDs can be generated from the command line using uuid.

$ npx uuid
ddeb27fb-d9a0-4624-be4d-4615062daed4

The default is to generate version 4 UUIDS, however the other versions are supported. Type uuid --help for details:

$ npx uuid --help

Usage:
  uuid
  uuid v1
  uuid v3 <name> <namespace uuid>
  uuid v4
  uuid v5 <name> <namespace uuid>
  uuid v7
  uuid --help

Note: <namespace uuid> may be "URL" or "DNS" to use the corresponding UUIDs
defined by RFC9562

`options` Handling for Timestamp UUIDs

Prior to uuid@11, it was possible for options state to interfere with the internal state used to insure uniqueness of timestamp-based UUIDs (the v1(), v6(), and v7() methods). Starting with uuid@11, this issue has been addressed by using the presence of the options argument as a flag to select between two possible behaviors:

Without options: Internal state is utilized to improve UUID uniqueness.
With options: Internal state is NOT used and, instead, appropriate defaults are applied as needed.

Known issues

React Native / Expo

Install react-native-get-random-values
Import it before uuid. Since uuid might also appear as a transitive dependency of some other imports it's safest to just import react-native-get-random-values as the very first thing in your entry point:

import 'react-native-get-random-values';
import { v4 as uuidv4 } from 'uuid';

Markdown generated from README_js.md by

uuid
Release 2.0.0

Release 2.0.0

11.0.3

11.0.2

11.0.1

11.0.0

11.0.0-0

10.0.0

9.0.1

9.0.0

9.0.0-beta.0

8.3.2

Documentation

uuid

Quickstart

API Summary

API

uuid.NIL

uuid.MAX

uuid.parse(str)

uuid.stringify(arr[, offset])

uuid.v1([options[, buffer[, offset]]])

uuid.v1ToV6(uuid)

uuid.v3(name, namespace[, buffer[, offset]])

uuid.v4([options[, buffer[, offset]]])

uuid.v5(name, namespace[, buffer[, offset]])

uuid.v6([options[, buffer[, offset]]])

uuid.v6ToV1(uuid)

uuid.v7([options[, buffer[, offset]]])

uuid.v8()

uuid.validate(str)

uuid.version(str)

Command Line

`options` Handling for Timestamp UUIDs

Known issues

React Native / Expo

Stats

Development practices

Releases

Contributors

uuid Release 2.0.0

Release 2.0.0 Toggle Dropdown 11.0.3 11.0.2 11.0.1 11.0.0 11.0.0-0 10.0.0 9.0.1 9.0.0 9.0.0-beta.0 8.3.2

Documentation

uuid

Quickstart

API Summary

API

uuid.NIL

uuid.MAX

uuid.parse(str)

uuid.stringify(arr[, offset])

uuid.v1([options[, buffer[, offset]]])

uuid.v1ToV6(uuid)

uuid.v3(name, namespace[, buffer[, offset]])

uuid.v4([options[, buffer[, offset]]])

uuid.v5(name, namespace[, buffer[, offset]])

uuid.v6([options[, buffer[, offset]]])

uuid.v6ToV1(uuid)

uuid.v7([options[, buffer[, offset]]])

uuid.v8()

uuid.validate(str)

uuid.version(str)

Command Line

options Handling for Timestamp UUIDs

Known issues

React Native / Expo

Stats

Development practices

Releases

Contributors

uuid
Release 2.0.0

Release 2.0.0

11.0.3

11.0.2

11.0.1

11.0.0

11.0.0-0

10.0.0

9.0.1

9.0.0

9.0.0-beta.0

8.3.2

`options` Handling for Timestamp UUIDs