ULID decoder & generator

26-character, lexicographically sortable identifiers. The first 10 characters are a 48-bit millisecond timestamp; the remaining 16 are 80 bits of entropy.

Crockford Base32

ulid-

decoded-

timestamp: -
unix millis: -
relative: -
timestamp part: -
randomness: -

about ULIDspec · ulid/spec

Layout (26 Crockford-Base32 chars):

10 chars - 48-bit millisecond timestamp.

16 chars - 80 bits of randomness.

Why ULID over UUID v4?

Lexicographic sort = chronological sort. Better DB-index locality. Case-insensitive, no hyphens.

- Alphabet: 0-9, A-HJKMNP-TV-Z (Crockford)

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