Overview

The UUID generator is an online tool for generating Universally Unique Identifiers (UUIDs) compliant with RFC 4122 (RFC 9562). It supports three versions — v1, v4, and v7 — and can generate up to 100 UUIDs at once.

How to Use

1. Select the UUID version (v1 / v4 / v7).
2. Specify the count in Number of UUIDs (up to 1,000).
3. Click the "Generate" button.
4. Copy and use the generated UUID list.

Specifications & Glossary

• Format: A UUID is a 128-bit identifier in the format xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx (M = version number, N = variant bits).
• UUID v1: Generated from a 60-bit timestamp combined with a MAC address or random value. Easy to sort chronologically, but may contain machine information.
• UUID v4: Generated with 122 fully random bits. Most widely used, highly privacy-safe, with an astronomically low collision probability (2 to the power of 122 combinations).
• UUID v7: Composed of a 48-bit Unix timestamp (millisecond precision) plus random bits. The latest specification defined in RFC 9562, it supports chronological sorting while offering the same randomness as v4. Advantageous for improving DB index efficiency.
• Collision probability: For UUID v4, even after generating 10 trillion UUIDs, the collision probability is below 0.00000001%. Duplicates are negligible in practice.

Use Cases

• Generating primary keys and record IDs for databases.
• Generating session IDs and request trace IDs for distributed systems.
• Uniquifying filenames and using as correlation IDs between microservices.