A UUID (Universally Unique Identifier) is a 128-bit number used to uniquely identify information in computer systems. It is represented as a 32-character hexadecimal string, often grouped into sections like 8-4-4-4-12 (e.g., 123e4567-e89b-12d3-a456-426614174000).

Online UUID Generator (Version 4)

Instantly create cryptographically strong, universally unique identifiers for your software and applications.

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What is a UUID and Why Use One?

A UUID (Universally Unique Identifier) is a 128-bit label used to uniquely identify information in computer systems. When generated according to standard methods, UUIDs are for practical purposes unique. Their uniqueness does not depend on a central registration authority or coordination between the parties generating them, unlike most other numbering schemes.

This tool generates Version 4 UUIDs, which are based on random numbers. The sheer number of possible v4 UUIDs is staggering—over 5.3 undecillion (5.3 x 10³⁶)—making the chance of a collision (generating the same UUID twice) astronomically low.

Common Use Cases

Database Primary Keys: Using UUIDs as primary keys allows you to generate IDs on different servers or in offline applications without conflicts when merging data.
Transaction IDs: Assign a unique ID to every transaction in a payment system, logging service, or any distributed system for easy tracking and debugging.
Session Identifiers: Create unique, hard-to-guess session tokens for user authentication.
File and Asset Naming: Avoid naming collisions when users upload files to a system by giving each file a UUID as its name.

Frequently Asked Questions

What is UUID version 4 (v4)?

UUID v4 is a version that is generated using random or pseudo-random numbers. Due to the massive number of possible combinations (2^122), the probability of two independently generated v4 UUIDs being the same is infinitesimally small. This makes it ideal for generating unique IDs without a central authority.

Are these UUIDs truly unique?

For all practical purposes, yes. The number of possible v4 UUIDs is so large that the chance of generating a duplicate is negligible. You would need to generate billions of UUIDs per second for many centuries to have a small chance of a collision.

Is this UUID generator secure?

Yes. This tool uses the built-in, cryptographically secure `crypto.randomUUID()` function available in modern web browsers. This is the recommended standard for generating secure random UUIDs on the client-side. All generation happens on your device, and no data is ever sent to a server.

100% Client-Side & Private

This tool runs entirely in your browser. We do not upload, store, or analyze any data. Everything you generate stays on your device.