What is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit label used to uniquely identify objects in computer systems. Standardised in RFC 4122, it is represented as a 32-character hexadecimal string split into five groups by hyphens, for example: 550e8400-e29b-41d4-a716-446655440000.
What is UUID version 4?
Version 4 UUIDs are randomly generated. They set a few specific bits to indicate the version and variant, but all remaining 122 bits come from a random source. This makes them statistically unique without requiring a central registry or coordination between systems — ideal for distributed applications.
When should I use a UUID?
UUIDs are widely used as primary keys in databases, as identifiers in REST APIs, as tokens for distributed systems, for session IDs, as unique file names, and in any context where you need a unique identifier that can be generated independently on different machines without collision risk.
How does this tool generate UUIDs?
The tool uses the browser's native crypto.randomUUID() API where available, falling back to a manual implementation using crypto.getRandomValues(). Both methods are cryptographically secure. Generation is entirely local — no UUIDs are transmitted or stored anywhere.