A ULID is a 26-character unique identifier that encodes a timestamp, so ULIDs sort chronologically while still being globally unique. This tool generates valid ULIDs — one or many — using a cryptographic random source, in your browser.
How to use it
- A ULID is generated on load.
- Set the quantity for multiple.
- Click Generate for fresh ones.
- Copy one, or all at once.
About ULID Generator
UUIDs are unique but random, which means they scatter in databases and indexes. ULIDs solve this by putting a millisecond timestamp in the first part of the identifier, so they are naturally ordered by creation time while remaining collision-resistant. That ordering improves database insert performance and makes IDs easier to reason about. ULIDs are also URL-safe and case-insensitive. This generator builds compliant ULIDs locally using Crockford base32 encoding and a secure random source.
FAQ
How is a ULID different from a UUID?
A ULID encodes a timestamp in its first characters, so ULIDs sort by creation time. UUID v4 is fully random and does not sort meaningfully.
Are ULIDs unique?
Yes, with very high probability. They combine a timestamp with 80 bits of randomness.
Are they URL-safe?
Yes. They use Crockford base32, which avoids ambiguous characters and is safe in URLs.