ULID Generator — Universally Unique Lexicographically Sortable ID
ULID is a 128-bit identifier encoded as 26 Crockford Base32 characters. The first 10 characters encode a millisecond timestamp; the remaining 16 are random. ULIDs are URL-safe, case-insensitive, and sort chronologically.
Example ULID
01ARZ3NDEKTSV4RRFFQ69G5FAVGenerate ULID
cf351fa8-a914-4b56-a341-adb31c2552b6Bit breakdown
FAQ
What is ULID and how does it differ from UUID?
ULID (Universally Unique Lexicographically Sortable Identifier) is similar to UUID v7 in being time-sortable, but uses Crockford Base32 encoding (26 characters vs 36 for UUID). ULIDs are URL-safe without encoding, case-insensitive, and visually easier to read and copy.
Is ULID monotonic within the same millisecond?
The standard ULID spec does not guarantee monotonicity within the same millisecond — the random bits are independently generated for each ULID. A monotonic ULID implementation increments the random portion for same-millisecond generation, guaranteeing strict ordering.
Can I convert a ULID to a UUID?
Yes — a ULID is a 128-bit value like a UUID, just encoded differently. You can decode the Crockford Base32 to get 128 bits and re-encode as a UUID hex string. Several libraries provide ULID ↔ UUID conversion utilities.
Need a different UUID version? The full generator supports v1, v4, v5, v7, and ULID.
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