UUID/GUID Generator

Generate Version 1 and Version 4 UUIDs (GUIDs).

Configuration

Generate

Output

Read-only

What is UUID/GUID Generator?

The UUID/GUID Generator is a convenient tool that allows you to easily generate identifiers that guarantee uniqueness across systems. UUID (Universally Unique Identifier) and GUID (Globally Unique Identifier) are 128-bit long unique identifiers with an extremely low probability of collision anywhere in the world.

This tool enables you to generate the two most commonly used types of UUID/GUID (versions 1 and 4) with customizable options. You can easily specify the format, character case, and quantity to improve your development and testing efficiency.

Key Use Cases for UUID/GUID

UUID/GUID are particularly useful in the following scenarios:

  • Database Primary Keys: Used as unique IDs for table primary keys that won't collide even in distributed systems
  • Distributed System Integration: Common keys for uniquely identifying data across multiple systems
  • Session Management: Used as session IDs in web applications
  • Transaction Identification: Unique identifiers for tracking processes and recording logs
  • File Name or Path Uniqueness: Identifiers to avoid conflicts with files of the same name

How to Use UUID/GUID Generator

Basic Usage

  1. Select Version: Choose the UUID version (1 or 4) you want to generate (default: version 4)
  2. Set Format Options:
    • Choose whether to include hyphens (e.g., 123e4567-e89b-12d3-a456-426614174000 or 123e4567e89b12d3a456426614174000)
    • Choose uppercase or lowercase (e.g., 123E4567-E89B-12D3-A456-426614174000 or 123e4567-e89b-12d3-a456-426614174000)
  3. Specify Quantity: Specify the number of UUIDs to generate at once, between 1 and 100 (default: 1)
  4. Click Generate: Press the "Generate UUID" button to create UUIDs/GUIDs based on your specified settings

Generation Examples

Version 4 (random-based) with hyphens in lowercase:

f47ac10b-58cc-4372-a567-0e02b2c3d479

Version 1 (timestamp-based) without hyphens in uppercase:

5A99E9E01C8A11E8AEFF362B9E155667

About UUID Versions

Version 1 (UUIDv1) - Timestamp-Based

Version 1 UUIDs are generated by combining the timestamp at the time of generation with a node ID (typically the device's MAC address).

Characteristics and Uses:

  • Can be sorted chronologically (since they embed the generation time)
  • Generate near-sequential values, which can improve database index efficiency
  • Useful when monotonically increasing values over time are required
  • Contain timestamps that allow later identification of the generation time

Considerations:

  • Include MAC addresses, so caution is needed in privacy-sensitive cases
  • Uniqueness may be affected by clock accuracy or adjustments due to timestamp dependence

Version 4 (UUIDv4) - Random Generation

Version 4 UUIDs are generated from completely random values. They use a cryptographically secure random number generator (CSPRNG) to produce unpredictable values.

Characteristics and Uses:

  • Completely random, so no information leaks from the generation pattern
  • Suitable for privacy-focused applications
  • Extremely low collision probability even when generated in parallel in distributed systems
  • The most commonly used UUID version

Considerations:

  • Randomness may reduce database index efficiency
  • Cannot be sorted by generation order due to complete randomness

UUIDv4 is also called GUID (Globally Unique Identifier) in Microsoft environments because the basic concept is the same. They are technically compatible.

Benefits of UUID/GUID for Identifier Generation

  • Minimized Collision Probability: Properly implemented UUID generation has a negligible collision probability (approximately 10^-37)
  • Compatibility with Distributed Systems: Multiple systems can generate independently without central coordination
  • Persistence: Once generated, a UUID remains permanently unique
  • Standardization: Standardized by ISO/IEC 9834-8:2005 and RFC 4122
  • Multi-language Support: Supported by generation and processing functions in almost all programming languages

Important Notes

  • The length of UUIDs (32 characters plus hyphens) may not be suitable when short identifiers are required
  • Version 4 UUIDs are randomly generated, so consecutive generations will not result in adjacent values
  • For critical security uses (such as encryption keys), consider using dedicated cryptographic random number generators