How to generate ULIDs
- Enter how many ULIDs you need.
- Press Generate to create them; copy them or download them as a text file.
- Paste any ULID into Inspect to see when it was created.
What is a ULID?
A ULID (Universally Unique Lexicographically Sortable Identifier) is a 128-bit ID written as 26 characters of Crockford Base32, such as 01ARZ3NDEKTSV4RRFFQ69G5FAV. The first 10 characters encode a millisecond timestamp and the last 16 are random. Because the timestamp comes first, ULIDs sort in creation order as plain strings, in any language and any database, without special collation.
Compared with a UUID, a ULID is shorter (26 instead of 36 characters), case-insensitive, URL-safe and avoids easily confused letters (I, L, O and U are not used). Those properties make ULIDs popular for event IDs, log entries, object keys in S3-style storage, and primary keys in systems such as DynamoDB, where sortable keys enable efficient range queries.
Like UUID v7, a ULID reveals its creation time. Randomness comes from the browser's cryptographically secure generator and all IDs are created on your device.
FAQ
Can I store a ULID in a UUID column?
Yes. Both are 128 bits, so a ULID can be converted to UUID format for storage. Many libraries provide this conversion.
Are ULIDs case-sensitive?
No. Crockford Base32 is case-insensitive, but the canonical form is uppercase.
What happens when two ULIDs are made in the same millisecond?
The random part differs, so they are still unique. Monotonic implementations also increment the random part so they stay in order.