UUID / GUID Generator
A new UUID, every time you load this page. Defaults to v4 (random) — pick a different version below. Generates up to 10,000 at a time, all in your browser.
Show all 0
What this tool does
This is a fully client-side UUID generator. Nothing you type or generate
leaves your machine. It supports every common UUID variant (v1, v3, v4,
v5, v7, and the nil UUID) plus output formatting: uppercase, braced
{...}, hyphen-stripped, and base64-encoded.
UUID v4 (the default)
UUID v4 is generated from 122 bits of randomness — there are about 5.3 × 1036 possible values, so the odds of generating the same one twice are vanishingly small for any practical workload. It's the right choice when you don't need ordering or determinism.
When to use other versions
- UUID v7 — time-ordered. Best when UUIDs are used as primary keys in databases (B-tree friendly).
- UUID v1 — timestamp + node ID. Reveals MAC address; rare in modern code.
- UUID v3 / v5 — derived from a namespace + name. Same input always produces the same UUID.
- Nil UUID — all zeros. Useful as a sentinel.
Privacy
All generation happens in your browser using
crypto.randomUUID() and the
uuid npm package. No
UUIDs are sent anywhere. There is no server side to this tool.
FAQ
What is a UUID?
A UUID (universally unique identifier), also called a GUID on Microsoft platforms, is a 128-bit number used to identify information in computer systems. UUIDs are typically written as 32 hex digits in five groups separated by hyphens, like 550e8400-e29b-41d4-a716-446655440000.
Are these UUIDs really random?
Yes. UUID v4 values are generated using your browser's crypto.getRandomValues(), a cryptographically secure random source. Nothing is generated on a server — your input never leaves your device.
Which UUID version should I use?
For most cases, v4 (random) is the right default — easy, no inputs needed. If you're storing UUIDs as primary keys in a database and care about index locality, prefer v7 (time-ordered). Use v3/v5 when you need a deterministic UUID derived from a name + namespace.
Is it safe to use UUIDs as security tokens?
UUID v4 has 122 bits of randomness — fine as an unguessable identifier in URLs (e.g. password reset links). It is not a substitute for a real session token or signed JWT, since it lacks expiration and integrity.
How many UUIDs can I generate at once?
Up to 10,000 in one click. Use the bulk button to download as CSV or JSON. Everything is generated client-side — no rate limit.