UUID generator
Processed in your browser · nothing is uploaded
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.
How to use the uuid generator
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.
Questions
122 random bits. You would need to generate billions per second for decades before a collision was likely.
A ULID is usually better. Random UUIDs scatter inserts across the index; a ULID sorts by time and keeps them sequential.
A shorter random identifier, 21 URL-safe characters by default, with comparable collision resistance.
No. They come from crypto.getRandomValues in your browser and are never transmitted.
Yes, the validate option checks the format and reports the version and variant.