Introducing the Random UUID Generator — v4, v7, and Nil in Your Browser

Every distributed system eventually needs identifiers that won’t collide — without phoning home to a central counter. That’s what UUIDs are for, and today we’re launching the Random UUID Generator to make them in your browser, the right way.

What it does

Pick a format — v4 (fully random), v7 (time-ordered), or the nil UUID — choose how many you need (up to 1000 at once), and generate. Toggle uppercase and hyphens to match whatever your system expects, then copy a single value or the whole list. The random bytes come from your browser’s crypto.getRandomValues, so v4 UUIDs are genuinely unpredictable rather than the weak output you’d get from Math.random.

Why v7 is a big deal

The headline addition is version 7. By putting a millisecond timestamp at the front of the value, v7 UUIDs sort by creation time — which means they append cleanly to database indexes instead of scattering random writes the way v4 keys do. If you’ve ever watched a UUID primary key fragment a B-tree, v7 is the fix. We dug into the trade-offs, the collision math, and when to choose each version in our UUIDs explained guide.

Why we built it

Plenty of free UUID tools quietly use a weak random source or only offer v4. We wanted one that uses a cryptographic source by default, supports the modern v7 format, generates in bulk for seed data, and never sends your values anywhere. It pairs naturally with our other security utilities like the Password Generator and Hash Generator.

Try it

It’s free, no sign-up, and runs entirely client-side — generate some UUIDs.