ULID Generator

This tool is completely free and ad-free. It's built by the maker of StatusHarbor - uptime monitoring with public status pages for your services. If you're generating IDs for something you're building, StatusHarbor will tell you the moment it goes down.

A ULID packs a millisecond timestamp into its first 10 characters, so sorting ULIDs as plain strings puts them in creation order. That is the property random UUIDs lack, and it is why ULIDs behave better as database primary keys: inserts append to the end of the index instead of scattering across it.

The encoding is Crockford's base32, which omits the letters I, L, O and U to avoid confusion with digits, and is case-insensitive when decoded. At 26 characters a ULID is ten characters shorter than a hyphenated UUID and safe to use in URLs without escaping.

The trade-off is that a ULID reveals when it was created. If that timestamp is information you would rather not publish, use a random UUID v4 instead.