UUID generator · formatUUID v7 — generator and how it works

When to use it

• The primary key of a large table: inserts go to the end of the index and pages do not fragment.
• IDs for events and logs that are handy to sort by the ID itself.
• A replacement for v1 and v6 when you want time inside but not the machine address.

How it differs from its neighbours

Against v4: v7 is ordered and kind to indexes, but it reveals the creation moment to the millisecond, which may be too much for public links. Against ULID: both sort by time and are built almost alike (48 bits of time first), but v7 is an RFC standard and fits a uuid column, while ULID is shorter to write — 26 characters instead of 36. Our generator is monotonic within a batch: inside one millisecond the random part grows by one.