uuid 
For the creation of RFC9562 (formerly RFC4122) UUIDs
- Complete - Support for all RFC9562 UUID versions
- Cross-platform - Support for...
- Secure - Uses modern
crypto API for random values
- Compact - Zero-dependency, tree-shakable
- CLI -
uuid command line utility
[!NOTE]
Starting with uuid@12 CommonJS is no longer supported. See implications and motivation for details.
Quickstart
1. Install
npm install uuid
2. Create a UUID
import { v4 as uuidv4 } from 'uuid';
uuidv4(); // ⇨ '9b1deb4d-3b7d-4bad-9bdd-2b0d7b3dcb6d'
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] | Uint8Array or Uint8Array subtype (e.g. Node.js Buffer). If provided, binary UUID is written into the array, 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(); // ⇨ '2c5ea4c0-4067-11e9-9b5d-ab8dfbbd4bed'
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] | Uint8Array or Uint8Array subtype (e.g. Node.js Buffer). If provided, binary UUID is written into the array, 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(); // ⇨ '1b9d6bcd-bbfd-4b2d-9b5d-ab8dfbbd4bed'
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] | Uint8Array or Uint8Array subtype (e.g. Node.js Buffer). If provided, binary UUID is written into the array, 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-64c1-9bdd-2b0d7b3dcb6d'
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 ensure uniqueness for UUIDs generated within the same millisecond time interval. Default = random value. |
[buffer] | Uint8Array or Uint8Array subtype (e.g. Node.js Buffer). If provided, binary UUID is written into the array, 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-745a-b76f-770d7b3dcb6d'
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 ensure 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.
Support
Browsers: uuid builds are tested against the latest version of desktop Chrome, Safari, Firefox, and Edge. Mobile versions of these same browsers are expected to work but aren't currently tested.
Node: uuid builds are tested against node (LTS releases), plus one prior. E.g. At the time of this writing node@20 is the "maintenance" release and node@24 is the "current" release, so uuid supports node@18-node@24.
Typescript: TS versions released within the past two years are supported. source
Known issues
"getRandomValues() not supported"
This error occurs in environments where the standard crypto.getRandomValues() API is not supported. This issue can be resolved by adding an appropriate polyfill:
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 
