UUID Generator

Generate cryptographically secure Version 4 UUIDs instantly online. Free UUID generator — one click to create and copy universally unique identifiers. No signup required.

Features

Common Use Cases

UUIDs are used as primary keys in databases, unique filenames for uploaded files, idempotency keys for API requests, session identifiers, and correlation IDs for distributed tracing. Version 4 UUIDs are randomly generated and have enough entropy (122 bits) that collisions are practically impossible, making them safe to generate client-side without coordination with a server.

How to Use

  1. Click Generate UUID to create a single cryptographically secure v4 UUID instantly.
  2. Use the Bulk Generate option to create multiple UUIDs at once if you need a batch for testing or seeding a database.
  3. Click Copy next to any UUID to copy it to your clipboard.
  4. The format is standard: 8-4-4-4-12 hexadecimal characters separated by hyphens, all lowercase.

Privacy & Security

All processing for UUID Generator runs entirely in your browser. Your data — whether text, files, or other content — is never transmitted to any server. DevToolHub has no backend that receives or stores your inputs. This means the tool works even offline once the page has loaded, and there is no risk of your data being intercepted or stored by a third party.

Frequently Asked Questions

What is a Version 4 UUID?

Version 4, which this tool generates, is the most common UUID type. It is created using random or pseudo-random numbers. Other versions use timestamps and MAC addresses (Version 1) or namespace-based hashing (Versions 3 and 5).

Are UUIDs secure or guessable?

Because a Version 4 UUID is generated from 122 bits of entropy, it is computationally infeasible to guess. Its randomness makes it suitable for use as an unguessable identifier, such as for a password reset link.

Can two generated UUIDs ever be the same?

Theoretically yes, but practically impossible. With approximately 5.3 undecillion possible values, you would need to generate approximately 2.71 quintillion UUIDs before having even a 50% chance of a single collision.

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