A UUID v4 is a randomly generated 128-bit identifier. It is commonly used for database IDs, request IDs, test data, and distributed systems where coordination is inconvenient.

Does this UUID generator use a backend?

No. UUIDs are generated directly in the browser using cryptographic randomness when available.

What is the difference between UUID and GUID?

GUID is a Microsoft-associated term for a globally unique identifier. In most everyday developer workflows, GUID and UUID refer to the same 128-bit identifier format.

Can I generate UUIDs without hyphens?

Yes. Use the no-hyphens output format to copy UUID values as 32 hexadecimal characters.

Free browser tool

UUID Generator for Random UUID v4 & GUIDs

Generate random UUID v4 identifiers for database rows, request IDs, test data, and distributed systems with browser-side generation.

UUID settings

Generate random UUID v4 values locally in your browser.

Try a common UUID task

How many UUIDs

Generate 1 to 100 identifiers at a time.

Output format

Generated UUIDs

Copy one identifier or the full batch as newline-separated text.

b7e558bc-cf4f-4745-b06f-a865eb3c8a44

f8057667-3d46-4786-8803-91e559eca596

6cd83236-5eb7-44e7-9790-adc86c2a37fa

4ea51822-9b69-41a2-bdbf-9e0160fcc814

2f482c97-4acc-4b5d-9cd2-7d04de54ee9e

Current batch

5 UUID v4 values generated with browser cryptographic randomness.

UUIDs are useful for test data, client-side drafts, and temporary identifiers. Use your database or backend as the final authority for production uniqueness.

Quick answer

A UUID v4 generator creates random 128-bit identifiers in the standard UUID format.

Use UUIDs for identifiers and test data, not for passwords, API keys, or access tokens.

Best inputs for UUID generation

Choose the right format

Standard hyphenated UUIDs are easiest to read, while no-hyphen values fit compact systems.

Generate only what you need

Bulk output is convenient for fixtures, but production IDs should usually be generated by the application.

UUID v4 format

A UUID v4 is a random 128-bit identifier with fixed version and variant bits.

xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx

The `4` marks version 4. The `y` position is one of 8, 9, A, or B in standard UUID v4 output.

Practical uses

UUIDs are useful for client-generated records, imports, fixtures, request tracing, temporary IDs, and distributed workflows where a central counter is inconvenient.

This tool is for identifiers, not passwords, secrets, API keys, or authentication tokens.

UUID method and example

UUID v4 values are random identifiers, not sequential IDs or secret tokens.

Format Assumption

xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx

The version position is fixed to 4. The variant position is one of 8, 9, A, or B.

Example use

Generate 20 UUIDs for test fixtures, import rows, local draft IDs, or request correlation examples.

Limitation

UUIDs are useful identifiers, but they should not be treated as passwords, API keys, or unguessable access tokens.

Common mistakes to avoid

These checks help prevent bad outputs, failed exports, and confusing results.

Using UUIDs as secrets

UUIDs are identifiers, not passwords, session tokens, reset links, or API keys.

Generating production IDs outside the app

Bulk output is useful for fixtures and examples. Production records should usually be generated by the system that owns the data.

Changing format accidentally

Hyphenated, uppercase, no-hyphen, and URN formats may not be accepted by the same database or API field.

Common use cases

Use UUIDs when you need independent identifiers instead of sequential counters.

Test fixtures

Generate IDs for sample rows, mock records, and local seed data.

Import rows

Create temporary identifiers for spreadsheet or CSV import examples.

Request tracing

Use UUID-shaped values in docs and debugging examples for correlation IDs.

Draft objects

Assign local IDs to prototypes, demos, and client-side examples.

Frequently asked questions

Are UUID v4 values certain to be unique?

No random identifier can be mathematically certain to be unique, but UUID v4 has such a large random space that collisions are extremely unlikely for normal application use.