UUID Generator

About this tool

A UUID is a 128-bit identifier designed to be unique without coordinating a central sequence. The UUID Generator creates cryptographically random version 4 identifiers in lowercase, uppercase or compact form and can generate a batch for fixtures, imports or test data.

Standard UUID text contains 32 hexadecimal characters and four hyphens. Removing hyphens changes only the presentation, not the underlying 128-bit value, but some databases and APIs expect the canonical hyphenated form. UUIDs are excellent public identifiers and distributed keys, yet they do not prove authenticity and should not be treated as secret access tokens. The generator uses the browser's secure random source when available.

How to use it

1. Choose how many UUIDs you need, up to the displayed batch limit.
2. Select lowercase or uppercase canonical output, or compact output without hyphens.
3. Generate the identifiers and check the format required by your database or API.
4. Copy the list or download it for fixture and import workflows.
5. Do not use a UUID by itself as authorization for sensitive data.

Useful ways to apply it

• Creating IDs for database seed records and test fixtures.
• Preparing client-generated identifiers for offline or distributed workflows.
• Replacing guessable sequential IDs in public URLs where enumeration is undesirable.
• Generating correlation IDs for logs and debugging examples.
• Testing validation rules for canonical, uppercase and compact UUID formats.

Worked example

Generate UUID v4

Example shape: 550e8400-e29b-41d4-a716-446655440000

Edge cases to check

• UUID uniqueness is probabilistic, not a central registry guarantee.
• Do not infer timestamps or identity from random v4 UUIDs.
• Authentication tokens may require a different threat model.

Known limitations

UUIDs are identifiers; they are not automatically authentication secrets.