← Home
δΈ­ζ–‡

ULID Generator

Time-sortable unique identifiers β€” modern UUID alternative

πŸ“₯ Parse a ULID

About ULID

  • ULID = Universally Unique Lexicographically Sortable Identifier (specification at github.com/ulid/spec)
  • 26 characters using Crockford Base32 (excludes I, L, O, U to avoid confusion)
  • Format: TTTTTTTTTT RRRRRRRRRRRRRRRR = 10-char timestamp (ms since epoch) + 16-char random
  • Sortable: lexical order = chronological order (great for database indexes)
  • 128 bits like UUID, same uniqueness guarantee

Why ULID over UUID v4

  • Sortable by time β€” natural insertion order in database indexes (no random scattering)
  • URL-safe β€” no hyphens, shorter (26 vs 36 chars)
  • Case insensitive β€” easier to read aloud or type
  • Used in modern systems: Vercel, Stripe, dating apps, distributed systems