UUID v4 Generator (RFC 4122, Batch)

Generate secure, random UUID v4 identifiers in your browser. Private by design—nothing leaves your device.

Controls

Ready.

Output

Tip: Press Ctrl/Cmd + Enter to regenerate with the same settings.

Legend (hyphenated view):
XXXXXXXX = time_low
XXXX = time_mid
4XXX = time_hi_and_version
XX XX = clock_seq (variant in high bits)
XXXXXXXXXXXX = node

Understanding UUID v4

A UUID (Universally Unique Identifier) is a 128-bit value used to identify resources across systems. UUID version 4 is generated from random numbers, yielding a very high probability of uniqueness.

Why Use UUID v4?

  • Uniqueness: 122 random bits make collisions astronomically unlikely.
  • Randomness: No timestamps or MAC addresses—harder to predict than v1.
  • Interoperability: Supported across languages, frameworks, and databases.

UUID v4 Structure

A UUID v4 has the form xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx:

  • time_low: 8 hex digits (red)
  • time_mid: 4 hex digits (green)
  • time_hi_and_version: starts with 4 (blue)
  • clock_seq: 4 hex digits (gold)
  • node: 12 hex digits (purple)

How This Tool Works

UUIDs are generated with the browser’s crypto.getRandomValues() to create 16 random bytes, then the version (4) and variant bits (RFC 4122) are set. Everything runs client-side—no data leaves your device.

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