UUID Generator
Generate cryptographically random UUID v4 identifiers in bulk.
UUID v4
Private by design. UUIDs are generated locally with the Web Crypto API. Nothing is transmitted or recorded.
How to use the UUID Generator
- Set how many identifiers you need.
- Toggle uppercase, hyphens and braces to match the format your target system expects.
- Press Regenerate for a fresh batch.
- Copy the whole list in one press.
A worked example
4 identifiers, hyphens on
9f1c2b7e-5a44-4e0b-b31c-6f0f1f8a2d4e
Version 4: 122 random bits from crypto.getRandomValues, with the version and variant fixed. Two of these colliding is not a risk you need to design around.
Frequently asked questions
What is a UUID v4?
A 128-bit identifier where 122 bits are randomly generated. It requires no central coordination, which makes it useful for IDs created independently on many machines.
Are these UUIDs safe to use in production?
Yes. They come from the Web Crypto API, which is a cryptographically secure random source, so the values are not predictable.
Can two UUIDs ever collide?
In theory yes, in practice no. Generating a billion UUIDs per second for a century still leaves the chance of a single collision negligible.
Should I use a UUID as a database primary key?
It works, but random UUIDs fragment B-tree indexes because inserts land in random positions. For high insert volumes consider UUID v7 or a sortable ID scheme instead.
About the UUID Generator
A version 4 UUID is 128 bits, of which 122 are random and 6 are fixed version and variant markers. It is written as 32 hexadecimal digits in a 8-4-4-4-12 pattern.
Randomness comes from crypto.getRandomValues, the same cryptographically secure source used for key material, not from Math.random. The collision probability is small enough to ignore: you would need on the order of 10^18 identifiers before a duplicate becomes likely.
Use the no-hyphen option for compact database columns and the uppercase option when matching a Microsoft-style GUID format.
Maintained by Ikonode. Last checked against the code on 11 September 2026.
What it does not do
- Version 4 only. If you need time-ordered identifiers for a database index, you want UUID v7 or ULID instead.
- Random means unsortable — v4 identifiers fragment a B-tree index when used as a primary key at volume.
- A UUID is unique, not secret. It is fine in a URL; it is not an access token.