Cereio

UUID Generator

Settings
Basic Settings
Quantity
UUID Information
UUID Version 4Random UUID with 122 bits of entropy
Format: xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxxLength: 36 characters (including hyphens)
Generated UUID
Click "Generate UUID" to create UUIDs

About UUID Generator

Generate standards-compliant UUID version 4 identifiers directly in your browser. The tool uses the Web Crypto API for its random bits and can create up to 50 lowercase, hyphenated UUIDs for database keys, API resources, tests, and distributed systems.

Key Features

Standards-compliant v4

Sets the required version and variant bits for UUID version 4.

Bulk Generation

Generate multiple UUIDs at once.

Web Crypto Randomness

Uses crypto.randomUUID or crypto.getRandomValues instead of Math.random.

100% Client-side

All generation happens in your browser - your UUIDs stay private.

Copy Support

One-click copy for individual or all UUIDs.

Batch Size

Create 1, 5, 10, 25, or 50 UUIDs at once.

How to Use

  1. 1Choose how many UUIDs to generate.
  2. 2Click 'Generate UUID' to create fresh version 4 identifiers.
  3. 3Copy individual UUIDs or all at once.

Pro Tips

  • 💡UUID v4 does not encode a timestamp, MAC address, or other device identifier.
  • 💡The version digit is 4 and the variant digit begins with 8, 9, a, or b.
  • 💡UUIDs are designed to be globally unique without central coordination.
  • 💡The probability of UUID collision is astronomically low (1 in 2^122 for v4).

Frequently Asked Questions

What is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit identifier designed to be unique across all time and space. Also known as GUID (Globally Unique Identifier).
Why does this generator use UUID v4?
UUID v4 is generated from random bits, does not reveal a timestamp or hardware address, and is widely supported for application identifiers.
Can two UUIDs ever be the same?
Theoretically possible but practically impossible. For v4, the probability is about 1 in 5.3 billion billion billion.
Why use UUIDs over auto-increment IDs?
UUIDs can be generated anywhere without coordination, are hard to guess, don't reveal record counts, and work across distributed systems.