UUID v4 Explained: Collision Probability and Real-World

UUIDs are 128-bit identifiers designed for distributed systems without a central authority. UUID v4 uses randomness, making collisions astronomically unlikely in practice.

How UUID v4 Works

Randomly generated with specific version and variant bits
No timestamp or MAC address information

Collision Probability

For practical purposes, the chance of collision is negligible. Use standard libraries and avoid custom PRNGs.

Use Cases

Database identifiers
Session tokens and resource IDs
Client-side unique keys in UI frameworks

Tools

Generate UUIDs with UUID Generator. Use bulk generation for testing workflows.

FAQ

Is it safe for security?

UUIDs are identifiers, not secrets. Do not use them as authentication tokens.

Should I use v1 or v4?

v4 avoids privacy concerns by not including MAC or timestamp. For most cases, v4 is preferred.

UUID v4 Explained: Collision Probability and Real-World Use Cases