UUID Generator
Generate Universally Unique Identifiers (UUIDs) with support for Version 1, Version 4, Nil, and Max UUIDs. Generate single UUIDs or create batches with formatting options.
About UUIDs
What is a UUID?
A Universally Unique Identifier (UUID) is a 128-bit identifier used in software construction. UUIDs are designed to be unique across all systems without requiring coordination.
UUID Format
UUIDs are typically displayed as 32 hexadecimal digits, displayed in five groups separated by hyphens: 8-4-4-4-12 for a total of 36 characters.
Version 4 (Random)
Version 4 UUIDs are generated using random or pseudo-random numbers. This is the most commonly used version and provides good uniqueness guarantees.
Version 1 (Time-based)
Version 1 UUIDs are generated based on the current timestamp and node information (MAC address). They provide temporal ordering but may reveal information about the generating system.
Special UUIDs
Nil UUID has all bits set to zero, while Max UUID has all bits set to one. These are special values defined in the UUID specification.
Common Uses
UUIDs are commonly used as database primary keys, session identifiers, file names, and anywhere a unique identifier is needed without central coordination.
UUID Standards
RFC 4122: The original UUID specification defining the format and generation algorithms.
RFC 9562: Updated UUID specification with new versions and improved guidance (draft).
Privacy & Security
All UUID generation is performed entirely in your browser using cryptographically secure random number generation when available. No data is sent to any server.
Version 4 UUIDs use crypto.getRandomValues() for better randomness, falling back to Math.random() in unsupported environments.