Create Random UUID v4 Identifiers
Produce one RFC 4122 version 4 UUID or a whole batch. Optional uppercase and hyphen-free output for whatever your system expects.
About this tool
A UUID, sometimes called a GUID, is a 128-bit label you can attach to a record or request without asking a server for the next number. Version 4 IDs are random, so two machines can mint them independently.
Generate a single value for a quick test or a list for seeding a database. The randomness comes from the browser cryptographic source, not Math.random.
- One UUID or a batch in a single run
- Uppercase and no-hyphen formatting
- Copy the whole list at once
Frequently asked questions
Can two UUIDs ever collide?
In theory yes, in practice the space is so large that accidental repeats are not a concern for normal applications.
Do I need an online service to issue UUIDs?
No. Version 4 values need only a random source, which every modern browser provides, so generation works offline.
Should I use v4 or a time-ordered variant?
Use v4 for general identifiers. If your database suffers from random index inserts, a time-sortable UUID variant may perform better.