Online Version 4 UUID Generator

Generate RFC 4122 compliant Universally Unique Identifiers (UUIDs) instantly with our web-based tool. Create Version 4 UUIDs for your applications, database records, or distributed systems. Our generator produces 100% unique identifiers that can be used for API keys, transaction IDs, session tokens, and more.

Key Features:
  • Generate multiple UUIDs simultaneously (up to 100 at once)
  • One-click copy to clipboard functionality
  • Supports UUID version 1, 4 and 7 specifications
  • No registration or personal data required
  • Mobile-friendly interface

What is a UUID?

A Universally Unique Identifier (UUID) is a 128-bit number used to uniquely identify information in computer systems. Also known as GUIDs (Globally Unique Identifiers), UUIDs are standardized by the RFC 4122 specification and are designed to provide a near-zero probability of duplication across space and time.

UUID Version Comparison

Version 1

Time-based

  • MAC address + timestamp
  • Guaranteed uniqueness
  • 48-bit MAC + 60-bit timestamp
  • Example: 123e4567-e89b-12d3-a456-426614174000
Version 4

Random

  • 122 random bits
  • Extremely low collision risk
  • No embedded information
  • Example: 550e8400-e29b-41d4-a716-446655440000
Version 7

Time-ordered

  • Unix timestamp + random
  • Chronological ordering
  • 48-bit timestamp + 74 random bits
  • Example: 061d0edc-e2fe-70a0-9b65-3c2d72c0c160

Common UUID Use Cases

Database Keys

Unique primary keys for distributed databases

API Security

Generation of secure API tokens and access keys

Session Management

Unique identifiers for user sessions

Frequently Asked Questions

Yes, when using our UUID generator, the probability of duplicate UUIDs is effectively zero. Version 1 UUIDs guarantee uniqueness through MAC address and timestamp combination, while version 4 UUIDs have 122 random bits resulting in 2¹²² possible combinations.

Key differences:
UUIDv1 UUIDv7
Uniqueness Source MAC address + timestamp Unix timestamp + random
Privacy Exposes MAC address No hardware identifiers
Sorting Time-based but not monotonic Strict time-ordered
Precision 100-ns intervals Millisecond precision

UUIDv4 and v7 can be used for tokens but with caveats:
  • ✅ Suitable for low-security scenarios
  • ❌ Not cryptographically secure by default
  • 🔒 Always combine with proper security measures:
    • Use HTTPS
    • Store hashed values (never raw UUIDs)
    • Implement expiration policies

For high-security applications, consider dedicated token generators with cryptographic signing.

Best practices for database storage:
  • 📦 Use database-native UUID types (PostgreSQL uuid, MySQL BINARY(16))
  • ⚡ Binary storage uses 16 bytes vs 36 chars for string
  • 🗂️ For MySQL: 
    CREATE TABLE items (
    id BINARY(16) PRIMARY KEY
);
  • 🔍 Always index UUID columns used in queries
  • 🌐 Consider ULID for smaller storage if sorting needed

Yes, but with limitations:
  • 🛠️ Use crypto.randomUUID() in modern browsers
  • 📦 Popular libraries:
    • uuid (npm package)
    • crypto-js
  • ⚠️ Client-side generation considerations:
    • Not secure for sensitive operations
    • No access to MAC address (can't generate true UUIDv1)
    • Time precision limitations for UUIDv7

For production systems, server-side generation is recommended.

Validation methods:
  • 🔍 Regular expression: 
    /^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/i
  • 🌐 Online validation tools

Version 3 (MD5) and 5 (SHA-1) are namespaced UUIDs that require:
  • 📛 A namespace UUID
  • 📝 A input string to hash
  • 🔒 Cryptographic hashing

We've focused on the most commonly used versions (1, 4, 7) for simplicity.

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