UUID Generator
Generate unique identifiers (UUIDs/GUIDs)
UUID v4
Random, most commonly used
UUID v1
Time-based, includes timestamp
Crypto Secure
Uses crypto.randomUUID()
What is a UUID?
A UUID (Universally Unique Identifier), also known as GUID (Globally Unique Identifier), is a 128-bit identifier that's guaranteed to be unique across all space and time. The standard format is xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx.
UUID Versions Explained
Version 4 (Random)
Generated using cryptographically secure random numbers. Most commonly used and recommended for security.
- ✓ Fully random
- ✓ No system info leaked
- ✓ Most secure option
Version 1 (Timestamp)
Based on timestamp and MAC address. UUIDs are sortable by creation time.
- ✓ Time-sortable
- ✓ Includes timestamp
- ⚠ May reveal system info
Nil UUID
Special UUID with all zeros. Used as a placeholder or null value in databases.
- ✓ Placeholder value
- ✓ Database null
- ✓ Default value
Common Use Cases
Database Primary Keys
Use UUIDs as unique identifiers without central ID generation
Session & API Tokens
Secure, unguessable tokens for authentication
Distributed Systems
Generate IDs independently across multiple servers
File Naming
Unique filenames for uploads and temporary files
Frequently Asked Questions
What is a UUID?
A UUID is a 128-bit identifier that's unique across all space and time. It's formatted as 32 hex characters in 5 groups separated by hyphens.
What's the difference between UUID and GUID?
They're essentially the same thing. GUID is Microsoft's term while UUID is the industry standard term. Both refer to the same 128-bit unique identifier format.
Can two UUIDs ever be the same?
Theoretically yes, but practically no. UUID v4 has 122 random bits, meaning collision probability is about 1 in 2^61 - you'd need billions of UUIDs to have any meaningful chance of collision.
Are these UUIDs cryptographically secure?
Yes! We use the Web Crypto API (crypto.getRandomValues) which provides cryptographically secure random numbers suitable for security applications.