Developers
UUID Generator
Random, spec-compliant UUID v4s — one or a hundred, copied in a click.
Need a unique identifier for a database row, a test API key, a demo dataset? This generator produces version 4 UUIDs compliant with RFC 4122, drawn from your browser’s cryptographic random number generator — the same source serious libraries rely on. Pick a quantity from one to one hundred, click, and copy the whole batch in one go: one UUID per line, ready to paste into a script, a seed file or a spreadsheet. Nothing is generated server-side and nothing is stored anywhere — the identifiers exist only on your screen until you copy them. Free, no sign-up, and usable as often as you like.
How does it work?
- Choose how many UUIDs to generate, from 1 to 100.
- Click “Generate” — the list appears instantly.
- Copy them all in one click, one UUID per line.
Frequently asked questions
What exactly is a UUID v4?
A 128-bit identifier written as 36 characters (8-4-4-4-12), of which 122 bits are pure randomness. Version 4 is recognisable by the “4” at the start of the third block. Unlike versions 1 and 7, it embeds no timestamp and no hardware address, so nothing about when or where it was created can be inferred.
Can two UUIDs collide?
In theory yes, in practice no: with 122 bits of randomness, you would need to generate about a billion UUIDs per second for decades before a duplicate becomes likely. You can use them as unique identifiers without any prior uniqueness check.
UUID or auto-increment ID in a database?
Auto-increment is compact and readable, but it leaks how much data you have and makes merging databases painful. UUIDs can be generated anywhere without coordination — ideal for distributed or offline systems. On very large tables, v4 UUIDs fragment indexes; time-sortable UUID v7 fixes that.
Is a UUID unpredictable enough to use as a secret?
A v4 UUID from a cryptographic generator — as used here — is unpredictable, and you will find them in password-reset or sharing links. But a real API secret deserves a dedicated token: longer, revocable and tied to permissions. A UUID identifies; it does not authenticate.