UUID Generator

Generate v4 UUIDs (Universally Unique Identifiers) instantly

About UUID Generator

The UUID Generator creates RFC 4122 version 4 Universally Unique Identifiers for database keys, correlation IDs, and client-side entity IDs. Backend and frontend developers use it to batch-generate random IDs in lowercase or UPPERCASE without writing a one-off script.

  • v4 UUIDs are random—do not expect sequential ordering for pagination.
  • Match the casing your database or API already stores to avoid duplicate-looking IDs.
  • Copy All when seeding fixtures so you keep a consistent set across environments.

About the UUID Generator

The UUID Generator creates random universally unique identifiers (also called GUIDs) such as 3f2b8c1e-9d4a-4b7e-a1c2-5e6f7a8b9c0d. A UUID is a 128-bit value that is, for practical purposes, unique across every computer in the world without any central coordination. That makes UUIDs ideal for database keys, file names, request IDs, API resources and test data.

How to Use the UUID Generator

  1. Choose how many UUIDs you need.
  2. Click Generate.
  3. Copy one UUID or the whole list.
  4. Paste them into your database script, code or test fixtures.

UUID Versions

Version 4 is generated from random numbers and is the most widely used. Version 1 includes a timestamp and machine identifier. Version 7 is a newer format that starts with a timestamp, so values sort in creation order, which is friendlier for database indexes. The version number appears as the first character of the third group.

UUIDs as Database Keys

UUIDs let you create IDs on the client or in multiple services without collisions, and they do not reveal how many records you have, unlike auto-increment numbers. The trade-off is size (16 bytes) and, for random v4 values, index fragmentation in clustered indexes. In SQL Server, consider NEWSEQUENTIALID() or UUID v7 when insert performance matters.

Generating UUIDs in Code

C#: Guid.NewGuid(). JavaScript: crypto.randomUUID(). Python: uuid.uuid4(). SQL Server: NEWID(). PostgreSQL: gen_random_uuid().

Frequently Asked Questions

Can two UUIDs ever be the same?

In theory yes, but the probability for v4 is so small that it can be ignored in real systems.

Is a GUID the same as a UUID?

Yes. GUID is Microsoft's name for the same 128-bit identifier format.

Should I use UUIDs as security tokens?

Random UUIDs are hard to guess, but for password reset links and API keys use a dedicated cryptographically secure token generator.

Uppercase or lowercase?

Both are valid. Lowercase is the most common convention.