ULID / UUID v7

Generate lexicographically sortable identifiers — ULID and UUID v7. Unlike UUID v4, these are timestamp-prefixed, so they sort naturally in databases and don't fragment B-tree indexes. Everything runs in your browser.

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SETTINGS
Why ULID & UUID v7 beat UUID v4 for databases

UUID v4 is fully random — great for security, bad for databases. Every insert lands in a random B-tree node, causing page splits, cache misses, and index fragmentation at scale. On a table with millions of rows this becomes measurably slow.

ULID and UUID v7 put the timestamp first. New IDs are always greater than older ones, so inserts go to the end of the index — no fragmentation. Postgres, MySQL 8, and most modern databases benefit immediately.

Property
UUID v4
ULID
UUID v7
Sortable
No
Yes
Yes
DB index friendly
No
Yes
Yes
Timestamp embedded
No
Yes (ms)
Yes (ms)
UUID-compatible format
Yes
No
Yes
Human readable
Medium
Better
Medium
Standard
RFC 4122
Community
RFC 9562

Choose ULID when you want a readable, Crockford Base32 encoded ID that's easy to copy and visually scannable. Choose UUID v7 when you need drop-in UUID compatibility — same column type, same tooling, just sorted.

Privacy note: All generation happens in your browser. No data sent anywhere.