Development

UUID Generator

Generate random v4 UUID identifiers for your applications.

How to use

  1. 1Click Generate.
  2. 2See the random UUID v4.
  3. 3Copy it for your project.

About

Generates random, unique UUID v4 identifiers — the universal standard for IDs in databases and APIs. Fast and no sign-up required.

What is a UUID and how to generate one

A UUID (Universally Unique Identifier) is a 128-bit identifier used to create unique keys in databases, APIs, and distributed systems. The UtilNexo generator creates random version-4 UUIDs, ready to use.

A UUID has the 8-4-4-4-12 format, totaling 36 characters (32 hexadecimal and 4 hyphens), like "550e8400-e29b-41d4-a716-446655440000". Version 4 is generated from random numbers, without relying on a clock or machine address.

In a UUID v4, the third group always starts with "4" (indicating the version) and the fourth group starts with 8, 9, "a", or "b" (variant). These reserved bits do not reduce security: about 122 bits of randomness remain.

The collision probability is astronomically small — to generate a duplicate, you would need billions of UUIDs per second for billions of years. That is why they are the standard for primary keys in modern systems.

Examples

  • Click Generate → 7f3c9a2b-5d8e-4f12-9a3b-1c2d3e4f5a6b (a random v4 UUID).
  • Each new click produces a completely different UUID, with no repetition.

Limitations

  • UUID v4 is random and carries no time or origin information, unlike v1 (based on timestamp and MAC address).
  • Because it is random, the order of UUIDs does not reflect creation order; for that, time-sortable v7 UUIDs exist.

How to use the UUID generator

  1. 1Click Generate.
  2. 2Copy the generated UUID.
  3. 3Paste it where needed (database, API, registration key).

Frequently asked questions

Can a UUID repeat?

In practice, no. The collision chance is negligible (about 1 in 2^122 for v4), even when generating billions of identifiers.

What is the difference between UUID and GUID?

They are essentially the same thing. GUID is the name Microsoft uses for the same concept of a universally unique identifier.

Should I use hyphens?

It depends on the system. Most APIs and databases accept the hyphenated format; some require the 32 characters without hyphens, which you can generate with the unformatted option.

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