About this tool
Why it exists.
A UUID gives a record a unique name without asking a central server for the next number. Version 4 UUIDs are random: this generator fills the required bits with cryptographically strong values from the browser's random number generator.
Generate up to 100 at once for fixtures, database seeds or test data. You can switch to uppercase or remove hyphens for systems with unusual constraints. Version 4 values are still not sequential, so do not use them as sortable primary keys if insertion order matters.
How to use it.
- Choose how many UUIDs you need.
- Set uppercase or hyphen-free formatting if required.
- Generate, then copy the full list or download a text file.
Good questions.
Are these UUIDs guaranteed to be unique?
They are statistically unique. A version 4 UUID has 122 random bits, so the chance of a collision within any realistic dataset is vanishingly small. But random generation can never provide an absolute mathematical guarantee.
What is the difference between UUID v1 and v4?
Version 1 is time- and node-based, so it can reveal timing and hardware information. Version 4 is purely random and avoids that leakage, which is why it is a better default for public identifiers.
Can I use UUIDs as database keys?
Yes, but random UUIDs scatter index insertions more than sequential integer keys. If write throughput is critical, consider UUIDv7 or a sequential integer alongside a UUID for external references.