Enter 1–100 ULIDs to generate
Generate sortable ULIDs online, free. A ULID (Universally Unique Lexicographically Sortable Identifier) is a 128-bit ID written as 26 Crockford base32 characters. The first 10 characters encode a 48-bit millisecond Unix timestamp and the last 16 hold 80 random bits, so ULIDs sort by creation time as plain strings. The format is defined in the open ULID spec (github.com/ulid/spec).
Each ULID's randomness comes from crypto.getRandomValues, and the timestamp is read from your device clock when you press Generate. Nothing is sent to a server. 100% free, no registration, and complete privacy — everything runs locally in your browser, so your data never touches a server.
Crockford base32 leaves out I, L, O and U, so IDs are easy to read aloud and type, and the output is always uppercase.
The leading timestamp means ULIDs sort in creation order as strings, which keeps database index inserts close to the end of the index.
Create one ULID or up to 100 at once for seeding tables, fixtures or log correlation IDs.
IDs are created in your browser and never uploaded, logged or stored.
A ULID is a 128-bit identifier written as 26 characters. It is made of a 48-bit millisecond timestamp followed by 80 random bits, encoded in Crockford base32. It is unique like a UUID, but it sorts by creation time when compared as text.
A UUID v4 is 122 random bits in the 8-4-4-4-12 hex layout and has no time order. A ULID has the same 128-bit size, but its first 48 bits are a timestamp, so sorted ULIDs follow creation order. Use v4 when you need pure randomness; use ULID when you want time-ordered keys.
They are ordered to the millisecond. Two ULIDs created in the same millisecond have random tails and may not sort in creation order. If you need strict ordering inside one millisecond, you need a monotonic generator that increments the random part, which this tool does not do.
No. The timestamp is visible in the first 10 characters, and the random part is only 80 bits. Use a token from a cryptographic generator for secrets, and use a ULID for identifiers.
No. ULIDs are generated in your browser from your device clock and the browser's random source. Nothing is sent to a server.
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