UUID Generator

What this UUID generator does

This tool creates RFC 4122 version 4 UUIDs: 128-bit identifiers intended to be unique without a central issuing server. They are useful for database records, local fixtures, event IDs, idempotency keys, trace IDs, and mock data where sequential identifiers would leak ordering or collide between systems.

How UUID v4 works

A version 4 UUID is mostly random. Certain bits are fixed to identify the UUID version and variant; the rest come from a cryptographic random source. In modern browsers this tool uses crypto.randomUUID() when available, and falls back to crypto.getRandomValues() with the correct version and variant bits set.

A UUID is not a secret. It is hard to guess accidentally, but if possession of an ID grants access, your application still needs authorization checks.

Common use cases

Primary keys for distributed systems where multiple writers create records.
Correlation IDs across logs and queues.
Test fixtures that must not collide with existing data.
Idempotency keys for retryable API requests.

Limitations

UUIDs are larger than integer IDs and do not sort by creation time. If you need sortable identifiers, consider ULID or UUID v7. If you need security tokens, generate dedicated random secrets with enough entropy and treat them as credentials.

Browser-only processing

UUID Generator runs as plain JavaScript inside this page using the browser's own Web Crypto and text APIs where the tool needs randomness or hashing. There is no request to our server when you press the tool buttons, so nothing you enter leaves your device through EmailGenerator.pro.

Privacy note

No input is sent anywhere by the tool. It operates entirely in your browser tab. You can verify this by opening the browser's network inspector and running the tool: execution does not create an outbound request.

Questions

Are UUIDs generated on the server?

No. They are created locally in your browser using browser cryptography APIs.

Can two UUIDs collide?

A collision is theoretically possible but astronomically unlikely for normal use.

Can I use a UUID as a password reset token?

Use a dedicated cryptographic token instead. A UUID identifies an object; it should not be your only security control.