UUID Generator

What is a UUID?

A UUID (Universally Unique Identifier) is a 128-bit identifier designed to be globally unique.

It is represented in a format such as 550e8400-e29b-41d4-a716-446655440000 and is commonly used for database record IDs, API keys, session management, and many other applications.

When this comes in handy

• You need an ID for a database primary key or API key: unlike sequential IDs, which are easy to guess, a UUID gives you a random, unique identifier with almost no setup.
• You need a large batch of dummy data for testing: specify how many you need and generate them all at once, instead of creating IDs one by one for seed or mock data.
• You need a value for a React key prop or a DOM element ID: get a guaranteed-unique string on the spot.
• Your existing system’s naming convention expects uppercase UUIDs: toggle between uppercase and lowercase output and paste the result directly where you need it.

Usage examples

Example 1: Generating a single UUID

Clicking “Generate” outputs one UUIDv4 in this format:

550e8400-e29b-41d4-a716-446655440000

It’s generated using crypto.randomUUID(), the Web standard API, producing the standard 8-4-4-4-12 hyphenated, lowercase hex format. The first character of the third group is always 4 (indicating version 4), and the first character of the fourth group is always 8, 9, a, or b.

Example 2: Generating an uppercase UUID

Turning on “Uppercase” keeps the same format but capitalizes the letters:

550E8400-E29B-41D4-A716-446655440000

Example 3: Generating multiple UUIDs at once

Setting the count to 5 outputs five UUIDs at once, one per line:

9b1deb4d-3b7d-4bad-9bdd-2b0d7b3dcb6d
c1a6a6b0-9e5a-4b1b-9f2e-3e1a0e4d5c8f
7e5f6a1b-2c3d-4e5f-8a9b-0c1d2e3f4a5b
3d2e1f0c-9b8a-4756-8354-1a2b3c4d5e6f
a4b5c6d7-e8f9-4a1b-8c2d-3e4f5a6b7c8d

You can copy the whole block and paste it directly into a CSV or a SQL INSERT statement as test data.