uuid generator

UUID Generator

Generate v4 (random) or v7 (time-ordered — sorts naturally, a common choice for database primary keys) UUIDs, one at a time or in bulk.

Generated with crypto.getRandomValues() · nothing leaves your browser

About v4 vs v7

v4 is 122 bits of cryptographically random data (6 bits are fixed for version/variant) — completely unpredictable, but random order means it doesn't sort well as a database primary key and can hurt index locality on inserts.
v7 (RFC 9562) embeds a 48-bit millisecond Unix timestamp in the high bits, followed by random bits — UUIDs generated later always sort after ones generated earlier, which keeps B-tree indexes append-friendly. Increasingly the recommended choice for new primary keys over v4 or auto-increment integers.
Both are generated with crypto.getRandomValues(), the browser's cryptographically secure random source — not Math.random().
Formatting (case, hyphens, braces, quotes) is applied after generation and doesn't change the underlying value.