UUID Generator

A UUID, or universally unique identifier, is a 128-bit identifier used to label data, resources, and objects without depending on a single central numbering service. It is usually displayed as a 36-character string containing hexadecimal characters and hyphens.

UUIDs are useful when identifiers must be generated independently across applications, devices, or distributed systems.

UUID v4 values are created primarily from random bits. The version field is fixed to4, and the variant field follows the UUID standard. The remaining bits come from the browser's cryptographically secure random source.

This UUID v4 generator produces lowercase values with the standard hyphenated layout.

1. Select a quantity from 1 to 100.
2. Select Generate UUIDs to replace the current result set.
3. Copy an individual UUID or use Copy All.
4. Use Download to save the current list as uuids.txt.

GUID, or globally unique identifier, is a term commonly used in the Microsoft ecosystem. Developers often use UUID and GUID for similar 128-bit identifier formats, but the terms should not be assumed to describe identical behavior in every historical implementation.

UUID v4 collisions are extremely unlikely when values are generated with a secure random source, but uniqueness is probabilistic rather than absolutely guaranteed. Systems with strict uniqueness requirements should still enforce a unique constraint where appropriate.

After reserving the version and variant fields, UUID v4 provides approximately 122 random bits. That large space keeps collision probability very low for ordinary application use, without making collisions theoretically impossible.

• Database identifiers generated across multiple services.
• Resource IDs in APIs and distributed systems.
• Test fixtures and temporary development data.
• Object, event, file, or request identifiers.

When UUIDs appear in API responses or test fixtures, theJSON Formatter can make the surrounding data easier to review. The Regex Testercan help inspect a UUID-shaped text pattern without proving identifier uniqueness.

A securely generated UUID v4 is useful as an identifier, but it is not automatically a replacement for a password, API secret, session token, or purpose-built authentication credential. Choose security controls based on the threat model of the application.