UUID Generator
Generate version 4 UUIDs with the browser's crypto API, in bulk, with uppercase and brace options.
Generate RFC 4122 version 4 UUIDs using the browser's crypto API.
About
5 version 4 UUIDs, generated locally with crypto.randomUUID. Bump the Regenerate field for a new batch.
Generating...About the uuid generator
A version 4 UUID is 122 random bits. The collision probability is small enough that you can generate identifiers independently on many machines and never coordinate, which is why they are used for distributed systems and client-generated keys.
These come from crypto.randomUUID, the browser's cryptographically secure generator.
How to use it
- 1Set how many you need.
- 2Choose uppercase or braces if your platform expects them.
- 3Change the Regenerate number for a new batch.
- 4Copy the list.
Questions
Can two UUIDs collide?
In theory. In practice you would need to generate billions per second for decades before collision became likely, so it is not a practical concern.
Should I use a UUID as a database primary key?
It works and avoids coordination, but random UUIDs fragment B-tree indexes because inserts land anywhere. UUID v7, which is time-ordered, is a better fit for that.
What does version 4 mean?
That it is generated from random data rather than from a timestamp or MAC address, which earlier versions used.