UUID Generator
Cryptographically random UUID v4, one or hundreds.
What is a UUID v4?
A UUID is a 128-bit identifier formatted as 8-4-4-4-12 hex digits. Version 4 generates 122 of those bits from a secure random source, which means the chance of two UUIDs ever colliding is negligible — that's why they're the standard primary key for distributed systems, databases and file names where coordination is impossible.
Generation uses your browser's crypto engine (not Math.random), so the output is suitable for real applications, not just demos. Generate a batch, copy them all, and paste into your seed data, test fixtures or migration scripts.
FAQ
Is a UUID the same as a GUID?
Practically yes — GUID is Microsoft's name for the same concept. UUID v4 and a random GUID are interchangeable in most contexts.
Can I use these as database primary keys?
You can, but note random UUIDs scatter writes across B-tree pages and make indexes larger than sequential IDs do. Many teams use them for external identifiers while keeping a sequential internal key.
What about UUID v7?
v7 embeds a timestamp for sortability — great for logs and event stores. Use a dedicated library if you need it; for pure uniqueness, v4 is perfect.