buncha/generators/uuid

UUID Generator

Stays on this device. UUIDs are generated using the browser's crypto.getRandomValues() — the same source the Web Crypto API uses for keys. No server round- trip, nothing logged.

Version

How many?

Format

About UUIDs. UUID v4 is the standard "random ID" for databases, distributed systems, and anywhere you need a globally-unique identifier without a central registry. The collision probability is so astronomically low that for practical purposes you can treat them as unique forever — generating one a second for ~85 years gives you a ~50% chance of seeing a collision. The NIL UUID (all zeros) is the canonical "no value" sentinel that some APIs use as a default. UUIDs are case-insensitive by spec, but pick one casing and stick to it across a system.

Pairs well with

Regex Tester

Test regular expressions with live highlighting an…

Diff Checker

Compare two texts and highlight differences.

JWT Decoder

Decode and inspect JSON Web Tokens.

Hash Generator

Generate SHA-1, SHA-256, SHA-384, and SHA-512 hash…

About UUID Generator

Generate cryptographically-strong UUIDs — v4 (random) or NIL — with one click. Bulk-generate up to 100, choose lowercase / UPPERCASE / no-dashes / braced format, copy individual or all.

UUID v4 is the standard 'random ID' for databases, distributed systems, and anywhere you need a globally-unique identifier without a central registry. The collision probability is so astronomically low that for practical purposes you can treat them as unique forever — generating one a second for ~85 years gives you a ~50% chance of seeing a collision.

UUIDs are generated using the browser's crypto.getRandomValues() — the same source the Web Crypto API uses for cryptographic keys. No server round-trip, nothing logged. The NIL UUID (all zeros) is the canonical 'no value' sentinel that some APIs use as a default.

Common questions

What format should I use?

Default lowercase with dashes is the most common. UPPERCASE matches some Microsoft conventions. No-dashes (32 hex chars) is compact for URL slugs. Braced ({xxxx-...}) is the Microsoft GUID convention.

Can I generate UUID v1 or v7?

v4 (random) and NIL are supported. v1 (timestamp + MAC) is a privacy hazard and we don't generate it. v7 (timestamp-prefixed) isn't yet but may be added.

Are UUIDs really unique?

Mathematically possible to collide, practically impossible. 122 bits of randomness in v4 means ~5.3 × 10^36 possibilities. You're more likely to be hit by lightning twice than to see a collision.

Everything happens on your device. Close the tab and it's gone.