Generate multiple ULIDs that stay sortable by time and easy to read.
ULID Generator
Generate multiple ULIDs that stay sortable by time and easy to read.
About ULID generation
Sortable IDs with monotonic batches
Each ULID starts with a millisecond timestamp encoded in the first 10 Crockford Base32 characters, followed by 16 random characters. When multiple IDs are generated in the same millisecond, the random part is incremented so the list still sorts in creation order.
Batch limit and uniqueness boundary
The page can generate up to 1,000 ULIDs at a time and uses an alphabet that avoids ambiguous characters. It is useful for sortable fixture data and database keys, but it is not a central registry that coordinates IDs across your production services.
FAQ
Common questions and answers about this topic.
What is a ULID?
A ULID (Universally Unique Lexicographically Sortable Identifier) is a unique ID that combines a millisecond timestamp with randomness, making it both unique and sortable by creation time.
How is ULID different from UUID?
ULID is sortable by time and uses a more compact Crockford Base32 encoding, while UUID v4 is fully random and uses hexadecimal. ULID is ideal when time-ordering matters.
When should I use ULID vs UUID?
Use ULID when time-ordering matters, such as database primary keys or event logs. Use UUID when wider compatibility with existing systems is more important.
Is my data sent to any server?
No, ULID generation is performed entirely in your browser. The identifiers are created locally with JavaScript and never transmitted anywhere.