UUID generator

Generates version 4 UUIDs from your browser’s cryptographic random source — 122 random bits each, enough that a collision is not something you will observe.

The three formats solve different problems and are worth telling apart. A v4 UUID is random, universally understood, and 36 characters. A ULID carries a timestamp in its first 48 bits, so a list of them sorts chronologically — which matters for database keys, because random UUIDs scatter inserts across a B-tree index and hurt write performance. A Nano ID is shorter, 21 characters by default, URL-safe, with the same practical collision resistance. Pick ULID for primary keys, Nano ID for anything appearing in a URL, and UUID when something else already expects one.