ULID Generator

Generate Universally Unique Lexicographically Sortable Identifiers — sortable, URL-safe, and 128-bit.

Count

Format

Why ULID over UUID?

Lexicographically SortableULIDs encode a millisecond-precision timestamp in the first 10 characters, so sorting them alphabetically also sorts them chronologically — perfect for databases.

MonotonicMultiple ULIDs generated within the same millisecond are guaranteed to be generated in order, preventing collisions without sacrificing randomness.

URL-SafeUses Crockford Base32 encoding — no hyphens, no mixed case ambiguity, no special characters. Safe to use in URLs, filenames, and log lines as-is.

128-bit Entropy48 bits of timestamp + 80 bits of cryptographic randomness. The same total entropy as a UUID v4, but with the added benefit of a sortable time component.

ULID Structure

01ARZ3NDEK+7S8EAGRQCG+XXXXXXXX

10 chars timestamp (ms precision) · 16 chars random (80-bit)