Are the UUIDs cryptographically random?

Yes. UUID v4 uses the browser crypto.getRandomValues, which is cryptographically secure on all modern browsers.

v4 or v7 — which should I use?

v7 for database primary keys because its timestamp prefix keeps B-tree indexes localized. v4 for everywhere uniqueness matters but ordering does not.

v4 collisions are effectively impossible: 2^122 random bits make duplicates astronomically unlikely.

Generators

Generate RFC 4122 UUID v4 (random) and v7 (time-ordered) identifiers. Bulk generate up to 1000 at a time.

Version

Fully random — suitable for most use cases. Uses crypto.randomUUID().

Count

v4 — Random

122 bits of cryptographically random data. Virtually zero collision probability (2¹²² possible values). The most widely used UUID version.

v7 — Time-ordered

48-bit millisecond timestamp prefix followed by random data. UUIDs sort chronologically, which eliminates B-tree index fragmentation in databases.

How to generate UUIDs

Generate RFC 4122 v4 and v7 UUIDs in bulk with one-click copy. Suitable for keys, tokens, and correlation IDs.

Pick the version
Choose v4 for random IDs or v7 for time-ordered IDs that work better as database primary keys.
Set the count
Generate a single UUID or dozens at once — useful for seeding test data.
Review the list
The generated UUIDs appear immediately. Click Regenerate for a fresh batch.
Copy to clipboard
Copy a single UUID or the entire list with one click.

? Are the UUIDs cryptographically random?: Yes. UUID v4 uses the browser crypto.getRandomValues, which is cryptographically secure on all modern browsers.
? v4 or v7 — which should I use?: v7 for database primary keys because its timestamp prefix keeps B-tree indexes localized. v4 for everywhere uniqueness matters but ordering does not.
? Is this UUID unique across every device that runs the tool?: v4 collisions are effectively impossible: 2^122 random bits make duplicates astronomically unlikely.