ULID Generator
Free online ULID generator tool, sortable unique identifiers
What is a ULID?
ULID (Universally Unique Lexicographically Sortable Identifier) is a 128-bit identifier that combines a timestamp with randomness. Unlike UUID v4, ULIDs are sortable by creation time, making them ideal for database primary keys and distributed systems where ordering matters.
▶What is the difference between ULID and UUID?
ULIDs are 26 characters (vs UUID's 36) and sortable by timestamp. UUID v4 is purely random with no ordering. ULIDs are better for database indexing because inserts are sequential.
▶Are ULIDs unique?
ULIDs combine a 48-bit timestamp (millisecond precision) with 80 bits of randomness. Within the same millisecond, the random portion provides 2^80 unique values. Collisions are extremely unlikely.