ULID Generator Online — Free
Runs 100% in your browser — your files never leave your device.
ULIDs give you the uniqueness of UUIDs plus lexicographic sorting by creation time, in a compact 26-character Crockford base32 string. Generate as many as you need for database keys or event IDs and copy them instantly — no server involved.
How it works
- 1
Generate
One click mints a fresh ULID from your browser's random source.
- 2
Inspect the format
The first 10 characters encode the timestamp, the rest are randomness.
- 3
Copy
Grab the identifier with one click and paste it into your schema.
About this tool
What a ULID is
A ULID is a 128-bit identifier like a UUID, but with two deliberate differences: it encodes a millisecond timestamp in its first ten characters and uses Crockford base32 (no I, L, O, U — letters that get misread), making every ULID both time-sortable and transcription-safe.
Why sortability matters
Random identifiers scatter across database indexes; time-ordered ones stack neatly, which keeps indexes compact and range queries fast. ULIDs sort correctly by creation time as plain strings — no extra timestamp column needed for ordering.
The Crockford alphabet
ULIDs exclude I, L, O, and U to prevent misreading (I/1/l, O/0) and accidental profanity. Generate as many as you need — each carries its own millisecond timestamp and 80 bits of randomness.
Frequently asked questions
ULID or UUID v7 — which should I use?
Both are time-ordered with random tails; ULID uses base32 with the friendly alphabet, UUID v7 fits the UUID format standards. Ecosystem compatibility decides — pick what your tooling expects.
Can two ULIDs generated in the same millisecond collide?
The 80 random bits after the timestamp make same-millisecond collisions vanishingly unlikely — and monotonic generation resolves ties by incrementing when needed.
Do ULIDs leak information?
They reveal creation time — that is their feature. If identifiers must reveal nothing, use random UUIDs v4 instead.