uuid generator
How to generate UUID and ULID
UUIDs and ULIDs give unique IDs without a central counter. UUID v4 is random; ULID is time-sortable.
UUID v4
128 random bits. Practical collisions are negligible. Great for PKs, request IDs, and idempotency keys.
ULID
Timestamp + randomness for approximate creation order—useful in logs and streams.
Generate in LedaTools
Pick UUID or ULID, set count, and copy. Created with browser crypto.
Not secrets
UUIDs identify; they don’t authenticate. Don’t use them as API keys.
Databases
Random UUIDs can fragment B-tree indexes; ULID/UUIDv7 help if insert order matters.
FAQ
What is UUID v4?
A random 128-bit ID with high entropy.
What about ULID?
A unique ID that sorts by time.
Are they unique?
Practical UUID v4 collisions are extremely unlikely.