UUID Generator
Generate random UUID v4 values using your browser’s cryptographic randomness.
Runs locally in your browser. Your input is never sent anywhere.
What a v4 UUID is
A version 4 UUID is 122 random bits laid out in the standard 8-4-4-4-12 form, with six bits fixed to mark the version and variant. There is no timestamp, counter or machine identifier in it — it carries no information about when or where it was made.
Where the randomness comes from
These are generated by your own browser through the Web Crypto API
(crypto.randomUUID, falling back to crypto.getRandomValues),
which is a cryptographically secure source. No value is requested from a server, so
nothing you generate here is ever known to anyone else.
Are collisions a real risk?
Not in practice. With 122 random bits you would need to generate around 2.7×1018 UUIDs before the chance of a single collision reached 50%. They are safe as database keys without coordination between the machines creating them.
A note on sorting
Because v4 is entirely random, values do not sort in creation order, which can hurt index locality on a busy table. Version 7 UUIDs embed a timestamp and sort chronologically; if that matters for your workload, use v7 instead.