About the ULID / UUIDv7
This generator creates time-sortable identifiers — ULIDs and UUID version 7 — directly in your browser. Both formats encode the creation timestamp in their leading bits, so when you sort the IDs as strings they also come out in chronological order. That gives you the uniqueness of a random ID with the natural ordering of an auto-incrementing key.
They are a strong fit for database primary keys, event and log identifiers, and any system where you want new records to cluster together for better index locality. ULID uses a compact 26-character Crockford Base32 encoding, while UUID v7 stays compatible with standard UUID columns and parsers. Everything runs locally in your browser, so the identifiers are generated on your device and nothing is uploaded.
How to use it
- Choose the format you need: ULID or UUID version 7.
- Set how many identifiers to generate.
- Click generate to create time-sortable IDs instantly.
- Copy a single value or the full list.
- Generate again later — newer IDs will sort after older ones.
Examples
- ULID for an event record: 01ARZ3NDEKTSV4RRFFQ69G5FAV, which sorts by creation time.
- UUID v7 for a database primary key that keeps inserts roughly in order on the index.
- Generate a batch of ULIDs for a stream of events so they remain naturally ordered.
Frequently asked questions
What makes ULID and UUID v7 time-sortable?
Both place a millisecond timestamp in their most significant bits, followed by random bits. Sorting them lexicographically therefore matches their creation order.
What is the difference between ULID and UUID v7?
ULID is a 26-character Crockford Base32 string, while UUID v7 follows the 128-bit UUID format and fits existing UUID columns and tooling. Both are time-ordered; UUID v7 is better when you need UUID compatibility.
Why use a time-sortable ID instead of UUID v4?
Random v4 IDs scatter across a database index, which can fragment it. Time-sortable IDs cluster recent inserts together, improving index locality and range queries by time.
Are these identifiers still unique?
Yes. After the timestamp portion, both formats add a large block of random bits, so IDs created in the same millisecond remain extremely unlikely to collide.
Does this run on a server?
No. The identifiers are generated entirely in your browser on your device, and nothing is sent to a server.
Can I expose the creation time from these IDs?
Yes, the leading bits hold the timestamp, so the approximate creation time can be decoded. Keep this in mind if you do not want IDs to reveal when a record was made.