CoderTools

UUID/GUID Generator

Generate unique identifiers (UUID/GUID) with customizable formats

Select UUID version to generate

Number of UUIDs to generate (1-100)

0 UUIDs

UUID Validator

UUID/GUID Generator Documentation

What is UUID/GUID?

UUID (Universally Unique Identifier) or GUID (Globally Unique Identifier) is a 128-bit number used to identify information in computer systems. UUIDs are designed to be unique across space and time without requiring a central authority.

UUIDs are commonly used in databases as primary keys, in distributed systems for unique identification, in session management, and for generating unique file names.

UUID Versions

Version 1 (Timestamp-based)

Generated using the current timestamp and MAC address. Contains time information and can be traced back to the generating machine.

Example: 6ba7b810-9dad-11d1-80b4-00c04fd430c8

Version 4 (Random)

Generated using random or pseudo-random numbers. Most commonly used version due to simplicity and no privacy concerns.

Example: 550e8400-e29b-41d4-a716-446655440000

NIL UUID

A special UUID consisting of all zeros, used to represent an empty or null UUID value.

Example: 00000000-0000-0000-0000-000000000000

UUID Format

A UUID is typically represented as a 36-character string in the format: 8-4-4-4-12 hexadecimal digits

xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx
  • M: Indicates the UUID version (1, 4, etc.)
  • N: Indicates the UUID variant (always 8, 9, a, or b)
  • x: Any hexadecimal digit (0-9, a-f)

Common Use Cases

Database Primary Keys

Use UUIDs as primary keys to ensure uniqueness across distributed databases without central coordination.

Session Management

Generate unique session identifiers for web applications to track user sessions securely.

File Naming

Create unique file names for uploads to prevent conflicts and ensure file uniqueness.

Distributed Systems

Identify entities in distributed systems without requiring coordination between nodes.

Best Practices

  • Use Version 4 (random) for most applications due to simplicity and privacy
  • Use Version 1 only if timestamp information is required
  • Store UUIDs in binary format in databases for better performance
  • Validate UUID format before processing to ensure data integrity
  • Consider collision probability: while extremely low, always handle duplicates gracefully
  • Use lowercase format for consistency unless uppercase is specifically required