UUID Generator
Generate random UUIDs (v4)
Frequently Asked Questions
What is a UUID?
UUID (Universally Unique Identifier) is a 128-bit identifier that is practically unique across all systems. The standard format is 8-4-4-4-12 hexadecimal characters (e.g., 550e8400-e29b-41d4-a716-446655440000).
What is UUID v4?
UUID v4 is generated using random numbers. It has 122 random bits, making collisions extremely unlikely (about 1 in 5.3 billion billion). Version 4 UUIDs have a '4' in the version position and 8, 9, a, or b in the variant position.
When should I use UUIDs?
Use UUIDs for database primary keys (especially in distributed systems), session IDs, file names, API keys, and any case where you need unique identifiers without a central authority. They're ideal when you can't coordinate ID generation.
Are UUIDs truly unique?
While not mathematically guaranteed unique, UUID v4 collision probability is so low it's practically impossible. You'd need to generate 1 billion UUIDs per second for 85 years to have a 50% chance of one collision.