UUID Generator

What is a UUID?

A UUID (Universally Unique Identifier), also known as a GUID (Globally Unique Identifier), is a 128-bit identifier that is unique across time and space. UUIDs are standardized by RFC 4122 and are used in databases, distributed systems, and APIs to identify resources without requiring a centralized ID authority.

The standard format consists of 32 hexadecimal digits displayed in 5 groups separated by hyphens: xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx, where the "4" indicates version 4 (random).

How to Use This Tool

1. Set the quantity of UUIDs you need (1 to 100)
2. Click Generate to create new UUIDs
3. Click any individual UUID to copy it, or Copy All for the full list

Common UUID Use Cases

• Database primary keys — Unique IDs without auto-increment conflicts
• API resource identifiers — Non-guessable IDs for REST and GraphQL
• Distributed systems — Generate IDs on any node without coordination
• Session tokens — Unique session identifiers for authentication
• File naming — Avoid collisions when storing uploaded files

Frequently Asked Questions

What is a UUID?

A UUID (Universally Unique Identifier) is a 128-bit number used to identify resources without a central authority. The format is 8-4-4-4-12 hexadecimal digits, like 550e8400-e29b-41d4-a716-446655440000.

Are v4 UUIDs truly unique?

For practical purposes, yes. A v4 UUID has 122 random bits, giving 5.3 x 10^36 possible values. You would need to generate 1 billion UUIDs per second for 85 years to have a 50% chance of a single collision.

What is the difference between UUID versions?

V1 uses the MAC address and timestamp (can leak device identity). V4 is purely random (most common). V5 uses SHA-1 hashing of a namespace and name. V7 (newest) combines a timestamp with random bits for sortability.

Can I use UUIDs as database primary keys?

Yes, but consider trade-offs. UUIDs prevent ID guessing and work across distributed systems, but they are larger (16 bytes vs 4-8 for integers) and can fragment B-tree indexes. UUID v7 solves the fragmentation issue by being time-sortable.

Is the UUID generated on the server?

No. UUIDs are generated entirely in your browser using the Web Crypto API (crypto.randomUUID), which provides cryptographically secure random numbers. Nothing is sent to any server.