UUID Generator

What is a UUID?

A UUID (Universally Unique Identifier) is a 128-bit value used to identify something — a database record, a session, an API request, a file — without needing a central authority to hand out IDs. Version 4 UUIDs are generated from random bits, and the chance of two ever colliding is so small it's treated as effectively zero, which is why they're the default choice for distributed systems where multiple services need to generate IDs independently.

This generator produces one or many v4 UUIDs at once, with optional uppercase formatting and the ability to strip the dashes for contexts that expect a plain 32-character hex string.

How to use it

How the UUIDs are generated

Each v4 UUID is generated using the browser's Web Crypto API (`crypto.randomUUID()`), a cryptographically secure random number source built into every modern browser — not a plain `Math.random()` fallback. Of a UUID's 128 bits, 122 are random; the remaining 6 are fixed to mark the value as version 4 and set the correct variant bits, per the UUID specification.

Features & benefits

Why this runs entirely in your browser

UUIDs are generated using the browser's own cryptographic random number generator, so there's no need to request them from a server. Everything runs in JavaScript locally in the tab, which means it keeps working offline once the page has loaded and no generated values are ever logged or transmitted.

Common uses

Generating primary keys for a database table, creating unique request or trace IDs for logging, seeding test data with realistic-looking identifiers, or generating a Nil UUID to test how a system handles that specific edge case.