UUID Generator

Generate cryptographically strong random UUIDs (v4) instantly. Perfect for database primary keys, API request IDs, session tokens, and testing workflows.

Unique IDs
Bulk Generation
Secure & Random
Generate UUIDs What is UUID?

UUID Generator

Choose how many UUIDs you need and click Generate. Each UUID is cryptographically random and globally unique.

Generation Settings

Generated UUIDs

Click "Generate UUIDs" to create unique identifiers.

Understanding UUIDs

Learn what UUIDs are, how they work, and when to use them in your projects.

What is a UUID?

A UUID (Universally Unique Identifier) is a 128-bit number used to uniquely identify information in computer systems. The standard format displays 32 hexadecimal digits in five groups separated by hyphens: 8-4-4-4-12 (e.g., 550e8400-e29b-41d4-a716-446655440000). UUIDs are designed to be globally unique without requiring a central authority.

UUID Version 4 (Random)

This tool generates Version 4 UUIDs, which are created using random or pseudo-random numbers. The probability of collision is so low (1 in 2122) that they're considered practically unique. Modern browsers use cryptographically strong random number generators, making V4 UUIDs suitable for security-sensitive applications.

Common Use Cases

  • Database Primary Keys: Use UUIDs instead of auto-incrementing integers for distributed systems.
  • API Request Tracking: Assign unique IDs to track requests across microservices.
  • Session Management: Generate secure session tokens that can't be guessed.
  • File Naming: Create unique filenames to prevent conflicts in cloud storage.
  • Testing & Development: Generate test data with guaranteed uniqueness.

Best Practices

Store UUIDs as binary (16 bytes) in databases rather than strings (36 characters) to save space and improve indexing performance. When exposing UUIDs in APIs, use the standard hyphenated format for consistency. For URL parameters, consider base64-encoding to reduce length while maintaining uniqueness.

Frequently Asked Questions

Common questions about UUIDs and their generation.

Are UUIDs truly unique?

While theoretically possible to generate duplicate UUIDs, the probability is astronomically low (about 1 in 5.3 × 1036 for V4). For practical purposes, they're considered globally unique without requiring coordination between systems.

Can UUIDs be used for security tokens?

Version 4 UUIDs generated with cryptographically strong random sources are suitable for session tokens and similar security use cases. However, for API keys or long-term secrets, consider additional entropy and purpose-built token generation libraries.

What's the difference between UUID formats?

The underlying UUID value is identical—only the text representation differs. Standard format includes hyphens (8-4-4-4-12), compact removes hyphens, uppercase converts letters to capitals, and braces add curly braces around the UUID. Choose based on your system's requirements.

Should I use UUIDs or auto-increment IDs?

UUIDs are better for distributed systems, merging databases, and preventing ID enumeration attacks. Auto-increment IDs are more efficient for single-database systems and provide natural ordering. Choose based on your architecture and security requirements.