How do I create a GUID / UUID?

The Problem

A universally unique identifier (UUID) is a 36-character-long alphanumeric string used to identify resources. A UUID is represented as hexadecimal digits in five groups separated by hyphens, for example, c75f7c66-e858-47d6-bb82-7ea5547c800c. Globally unique identifier (GUID) is another name for this type of identifier.

A computer generates a UUID by creating a very large, random number. The probability of a duplicate being created is extremely small. It can be useful to quickly assign a unique ID for a record in a database, an ID that will be unique across multiple database tables or databases.

How do you create a UUID?

The Solution

You can use the Web Crypto API that’s accessed through the global crypto property. It’s a Crypto object that has a randomUUID() method that returns a randomly generated UUID. It uses a cryptographically secure number generator.

const uuid = crypto.randomUUID();
console.log(uuid); // '398de222-5bf9-4754-8e3e-011a55307014'

This method can only be used in secure contexts, which includes pages delivered over HTTPS or served locally using URLs such as http://127.0.0.1 and http://localhost.

It has good browser support. If you need it to work in browsers that don’t support it or in non-secure contexts, you can use the uuid library. You can also use this library in server-side JavaScript.

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

In Node.js, you can use the randomUuid() method of the Node.js crypto module.

These methods generate a RFC 4122 UUID.