UUID Generator

Generate random UUIDs (v4) instantly.

Generator

Click "Generate" to create UUIDs.

About UUID Generator

A UUID (Universally Unique Identifier) is a 128-bit identifier standardized by RFC 4122. UUID version 4 (v4) generates identifiers using random or pseudo-random numbers, resulting in approximately 5.3 × 1036 possible values — making collisions virtually impossible. The standard format uses 36 characters: 32 hexadecimal digits separated by 4 hyphens (8-4-4-4-12).

This tool generates UUID v4 values using the browser's Web Crypto API (crypto.randomUUID() or crypto.getRandomValues()), which provides cryptographically secure random numbers. This means the generated UUIDs are suitable not only for general-purpose identification but also for security-sensitive use cases like session tokens and API keys. You can generate multiple UUIDs at once and copy them all with a single click.

How to Use UUID Generator

  1. Set the Number of UUIDs you want to generate (1 or more).
  2. Click Generate to create the UUIDs. They appear in the output area.
  3. Use Copy all to copy all generated UUIDs to your clipboard at once.

Key Features

  • Cryptographically secure — Uses the Web Crypto API for truly random values
  • Batch generation — Generate multiple UUIDs at once
  • Standard format — Output follows RFC 4122 UUID v4 format (8-4-4-4-12)
  • One-click copy — Copy all generated UUIDs with a single click
  • 100% client-side — No server communication; UUIDs are generated in your browser

When to Use This Tool

  • Generating unique primary keys for database records
  • Creating session identifiers or API tokens for web applications
  • Assigning unique IDs to files, uploads, or resources
  • Testing and development — quickly generating placeholder identifiers
  • Distributed systems where globally unique IDs are needed without coordination

Technical Details

UUID v4 is defined in RFC 4122. The format is xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx, where each x is a random hexadecimal digit and y is one of 8, 9, a, or b (indicating the RFC 4122 variant). The "4" in the third group identifies it as version 4 (random). This tool uses crypto.randomUUID() when available (modern browsers) or falls back to crypto.getRandomValues() for generating the random bytes. The Web Crypto API provides cryptographic-quality randomness, making these UUIDs suitable for security-sensitive applications. All generation happens in JavaScript within your browser.

Conclusion

UUID Generator is a fast, secure tool for creating universally unique identifiers directly in your browser. With cryptographically secure randomness, batch generation, and zero server communication, it is perfect for developers, testers, and anyone who needs reliable unique IDs. To verify existing UUIDs, use the UUID Validator.

Frequently Asked Questions

What is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit value displayed as 36 characters in the format 8-4-4-4-12 (hex with hyphens). UUID v4 uses random values, making collisions virtually impossible.
Are these cryptographically secure?
Yes. The tool uses the Web Crypto API (crypto.randomUUID or crypto.getRandomValues) to generate random bytes, making the UUIDs suitable for security-sensitive applications.
Is any data sent to a server?
No. UUIDs are generated entirely in your browser using the Web Crypto API. Nothing is uploaded or stored on any server.
What is the probability of a UUID collision?
Extremely low. UUID v4 has approximately 5.3 × 10^36 possible values. You would need to generate about 2.71 × 10^18 UUIDs to have a 50% chance of a single collision — far beyond any practical use case.