UUID v4
Version 4 UUIDs are random identifiers commonly used for fixtures, tests, distributed records and temporary IDs.
Browser-based developer tools
UUID Generator
Generate random UUID v4 values for tests, fixtures, database rows and API examples.
UUIDs are generated locally with browser cryptographic randomness when available.
Reference notes
Random identifiers for development
Local generation
Values are generated in the browser and are not requested from a server.
Collision safety
UUID v4 collisions are extremely unlikely, but production systems should still enforce uniqueness where it matters.
Frequently asked
UUID generator questions
What makes UUID v4 different from other versions?
Version 4 UUIDs are generated from random or pseudo-random numbers, unlike version 1 which encodes a timestamp and MAC address, or version 5 which is derived deterministically from a namespace and name.
Can two generated UUIDs ever collide?
The probability is astronomically small given the 122 bits of randomness in a v4 UUID. In practice, UUID v4 is treated as unique for database primary keys and distributed system identifiers.
Are UUIDs generated locally?
Yes. Generation uses the browser's cryptographically secure random number source, so no request is sent to a server and no generated value is logged.