Is UUID v7 faster than v4 for a primary key?

For write-heavy tables, yes: sequential keys avoid random B-tree page splits, which is why Postgres, MySQL and SQLite all insert v7-shaped keys noticeably faster than v4-shaped ones at large table sizes.

Can v7 UUIDs be sorted as text?

Yes. The timestamp is big-endian, so plain lexicographic order over the hyphenated string matches chronological order — no custom collation needed.

Does my database support v7?

Any column that stores a 36-character or 16-byte UUID accepts v7 unchanged; it is still a UUID, just with a different version nibble. Older validators that hard-reject anything but version 4 are the usual sticking point.

Generators & Utilities Ready to use

UUID v7 Generator

Create time-ordered UUID v7 identifiers whose leading 48-bit timestamp keeps database indexes append-friendly. Copy, download or seed a batch.

Operation

Inspect reads the version, variant, node and (for v1/v7) the creation time baked into an id you paste.

ID format

v4 for opaque primary keys; v7 or ULID when rows should insert in creation order.

How many

Written as

Ignored for ULID, which never carries hyphens.

UPPERCASE

Seed (optional)

Set a seed to get the same batch again — useful for fixtures and tests.

ID to inspect

This tool runs entirely in your browser. Your input never leaves your device.

About UUID v7 Generator

RFC 9562 defines UUID v7 as the version built for databases. The first 48 bits are a big-endian millisecond timestamp, then the version nibble, then 74 random bits. Because the timestamp leads, ids minted later sort after ids minted earlier — as hex, as text, and therefore as a B-tree key.

That ordering is the whole point. A v4 primary key is uniformly random, so every insert lands somewhere in the middle of the index, splitting pages, waking cold data and growing the write-ahead log. A v7 key appends. You keep the no-coordination property of a random UUID and the insert locality of an auto-increment column, without a sequence that a sharded or offline system has to negotiate.

This generator writes the real layout: your machine clock in the first 12 hex digits, version 7 in the thirteenth, the RFC 4122 variant bits in the sixteenth, randomness everywhere else. Use the inspect operation on the UUID Validator page to read a v7 id back and confirm the timestamp it carries. The trade-off to know about is disclosure — anyone holding the id can compute the millisecond it was created.