UUID Generator

Generate cryptographically secure random v4 UUIDs in your browser. Bulk generate up to 100 at once, copy with a single click.

About the UUID Generator

A UUID (Universally Unique Identifier) version 4 is a 128-bit identifier generated using random numbers. Unlike version 1 UUIDs which embed a MAC address and timestamp, v4 UUIDs reveal nothing about the machine or time they were created on, making them preferable for privacy-sensitive applications.

This tool uses the browser's crypto.randomUUID() function — a cryptographically secure random number generator built into every modern browser. The values are never transmitted to any server; generation is entirely local.

Common uses include: database primary keys, idempotency keys for API requests, session identifiers, file names for uploaded assets, and correlation IDs in distributed systems.

Frequently Asked Questions

What is a UUID?

A UUID (Universally Unique Identifier) is a 128-bit identifier standardised in RFC 4122. The v4 variant uses random data and has an astronomically low probability of collision, making it safe for use as primary keys, session tokens, and correlation IDs without a central registry.

Are these UUIDs truly random?

Yes. This tool uses the browser's built-in crypto.randomUUID() function, which is backed by a cryptographically secure pseudo-random number generator (CSPRNG). The output is suitable for security-sensitive use cases.

What is the format of a v4 UUID?

A v4 UUID follows the pattern xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx where x is a random hex digit, 4 is fixed to indicate version 4, and y is one of 8, 9, a, or b (indicating the RFC 4122 variant).

Can I generate multiple UUIDs at once?

Yes — set the count field to any number between 1 and 100 and click Generate. The output area will list one UUID per line, ready to copy.

Do generated UUIDs leave my browser?

No. All generation happens client-side using the Web Crypto API. Nothing is sent to a server.

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