Guide - Developer
Understand UUIDs - unique IDs used across databases and APIs - and generate one instantly.
A UUID (Universally Unique Identifier), also called a GUID, is a 128-bit value written as 36 characters like 550e8400-e29b-41d4-a716-446655440000. It is designed so two systems can each create IDs that never collide, without a central authority.
Use UUIDs as primary keys, request IDs, file names, or any identifier that must be unique across systems. Version 4 (random) is the common choice and is generated entirely in your browser.
Auto-increment numbers are short but reveal counts and require a single database to assign them. UUIDs are longer but can be generated anywhere, in parallel, with effectively zero chance of collision.
Unique IDs prevent data clashes when systems merge or sync. UUIDs make distributed and offline-first apps far simpler.
Yes - GUID is Microsoft's name for the same 128-bit identifier. They are interchangeable.
In practice, no. Version 4 UUIDs have so many possible values that a collision is astronomically unlikely.
Tools and guides to go further.