UUIDs Explained: When and How to Use Universally Unique IDs

What Is a UUID?

A UUID (Universally Unique Identifier) is a 128-bit identifier that's guaranteed to be unique across all systems without central coordination.

Example: 550e8400-e29b-41d4-a716-446655440000

UUID Versions

Version	Based On	Use Case
v1	Timestamp + MAC address	Ordered by time, reveals device info
v4	Random	Most common, no information leakage
v5	Namespace + name (SHA-1)	Deterministic from input
v7	Timestamp + random	Sorted, modern alternative to v1

### UUID v4 Is King v4 UUIDs are generated from random numbers, making them:

• Unpredictable (no information leakage)
• Collision probability: 1 in 2^122 (virtually impossible)
• No coordination needed between systems

UUID vs Auto-Increment IDs

Feature	UUID	Auto-Increment
Uniqueness	Global	Per-table
Predictability	None	Sequential
Size	36 chars	1-10 digits
Performance	Slightly slower	Faster
Distributed systems	✅ Perfect	❌ Requires coordination
Security	✅ Not guessable	❌ Enumerable

### When to Use UUIDs

• Distributed systems — multiple databases generating IDs independently
• Public-facing IDs — URLs, API responses (prevents enumeration attacks)
• Merge scenarios — combining data from multiple sources
• Offline-first apps — generate IDs before syncing

Generate UUIDs with Fluranto

The UUID Generator creates v4 UUIDs instantly:

• Generate single or bulk UUIDs
• Copy to clipboard
• Use in your database, API, or configuration

Related Tools

• Hash Generator — create deterministic hashes from input
• Password Generator — random strings for authentication