Generate IDs that sort by creation time

UUIDs are random; ULIDs encode time so sorting the string sorts the chronology — useful for log and record keys.

Tools used in this guide

ULID generator
UUID generator
UUID inspector

The job

Database keys that sort chronologically without a separate timestamp index: that's the ULID pitch. The first 48 bits are the millisecond timestamp, so string order = creation order (within the same ms they still compare fine).

Generate a batch

Pick a count, click generate, copy the list. IDs are 26 characters of Crockford Base32 — no ambiguous I, L, O, U, safe for URLs and filenames.

Example shape: 01H9ZEXAMPLE… — the timestamp prefix shares leading characters for IDs minted close together.
Up to 200 per click; everything is generated in-browser, nothing is sent anywhere.

ULID vs UUID

Use ULIDs when sortability helps (event logs, append-order records). Use UUID v4 when you need the standards-track format or want IDs that reveal nothing about timing — ULIDs leak their creation millisecond by design.