Random UUIDs, one or a hundred at a time
Generate version 4 UUIDs instantly for database keys, test fixtures, filenames, API identifiers and anywhere else you need a value that will never clash with another. The generator uses your browser’s secure random source, so every UUID is genuinely random, and nothing is sent to a server.
How to use the UUID generator
- Generate in bulk: choose how many you need, from 1 to 100, and press Generate. The full list appears below, ready to copy or download as a text file.
- Copy one or all: each UUID has its own copy button, and Copy all grabs the whole list in one click for pasting into a spreadsheet, seed file or test script.
- Validate an existing UUID: paste any value into the validator to check its format and read its version and variant. This is handy when debugging data imported from another system.
Where UUIDs show up
- Database primary keys: unlike auto-incrementing numbers, UUIDs can be generated on any server or device without coordination, which is why distributed systems prefer them.
- File and object names: uploads, exports and cached files get UUID names so two users’ files never overwrite each other.
- API and event identifiers: requests, jobs and webhook deliveries carry UUIDs so retries and duplicates can be detected safely.
- Test data: seed scripts generate fresh UUIDs per run instead of reusing fixed examples that might collide with real data.
UUID format, decoded
A UUID has five groups of 8, 4, 4, 4 and 12 hex digits, separated by hyphens. The first digit of the third group is the version: 4 for random. The first digit of the fourth group encodes the variant and is 8, 9, a or b for the standard layout used today. The well-known nil UUID is all zeroes, and it means "no value" rather than a real identifier. The validator below reads these positions for you, so you do not have to count characters yourself.