UUID Generator
Free UUID generator. Create version 4 universally unique identifiers for databases, APIs and apps. Generate up to 50 at once with one click. No signup.
About this tool
A UUID, or Universally Unique Identifier, is a 128-bit label used to identify records, files, sessions and objects in software. Developers use them as database keys, API tokens and transaction IDs because they can be generated anywhere without a central authority handing them out.
This free tool generates version 4 UUIDs, the random kind, instantly in your browser. Generate one or fifty at a time, copy them with a single click, and paste them straight into your code. Nothing is uploaded or logged.
How to use
Enter how many UUIDs you need, from 1 to 50, and click Generate UUIDs. Each identifier looks like 550e8400-e29b-41d4-a716-446655440000: 32 hexadecimal digits in five groups. Use the Copy All button to copy the whole list at once, one per line.
Paste them into database seed files, test fixtures, config files or anywhere a unique string is required. Every click produces a brand-new set, so you will never accidentally reuse one.
The math behind it
A version 4 UUID contains 122 bits of randomness, with 6 bits fixed to mark the version and variant. Those 122 random bits give 5.3 undecillion possible values, an unimaginably large space. This tool fills the bits using your browser's cryptographic random generator.
Because the space is so vast, two independently generated UUIDs will essentially never collide. That is the whole point: independent systems can mint identifiers without checking with each other, and uniqueness is still practically guaranteed.