Web Dev Helpers
UUID Generator
Generate UUIDs - v1 (time), v4 (random), v7 (sortable time).
1 V4 UUID
afd3e590-024d-44cd-a020-a13b9bd64939
About this tool
UUIDs are 128-bit identifiers used for primary keys, request IDs and idempotency tokens. Pick a version, generate one or many, and copy.
FAQs
v1 vs v4 vs v7?
v1 embeds a timestamp + MAC. v4 is fully random. v7 is timestamp-prefixed random - sortable like ULIDs but in standard UUID format.
Should I use v4 or v7 for primary keys?
v7 - newer rows sort to the end, which is much friendlier on B-tree indexes than fully random v4.
Is uniqueness guaranteed?
Practically yes for v4 (collision odds vanishingly small) and v7. v1 needs a unique node ID to be truly unique across machines.