UUID Generator vs ULID Generator
UUID v4 and ULID both produce unique identifiers without coordination, but ULIDs sort chronologically while random UUIDs do not — which matters a great deal to database indexes.
UUID Generator
UUID generator — create UUID v4 (cryptographically random) or UUID v7 (time-ordered, RFC 9562) identifiers instantly. Bulk-generate up to 100 UUIDs at once and download as a text file. UUID v7 is ideal for database primary keys — it is lexicographically sortable and avoids index fragmentation.
- ✓RFC 4122 standard, universally supported
- ✓36 characters with hyphens, 122 random bits
- ✓Random ordering — scatters B-tree index writes
- ✓Reveals nothing about creation time
- ✓UUID v7 exists if you want time ordering in the same standard
ULID Generator
ULID generator — generate Universally Unique Lexicographically Sortable Identifiers. 48-bit timestamp prefix + 80-bit random component, Crockford Base32 encoded. Time-ordered, URL-safe, case-insensitive. Better than UUID v4 as a database primary key.
- ✓26 characters, Crockford Base32, URL-safe
- ✓48-bit millisecond timestamp + 80 random bits
- ✓Lexicographically sortable by creation time
- ✓Sequential writes keep index inserts local
- ✓Leaks approximate creation time by design
When to use each
Consult the tool documentation for guidance.
Consult the tool documentation for guidance.