UUID v4 Generator

Generate RFC4122 UUID v4 values in bulk and copy them as plain lines.

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How it works

We call crypto.randomUUID() from the browser's built-in Web Crypto API, which generates a cryptographically random UUID v4 compliant with RFC 4122. In older browsers without that method, we fall back to crypto.getRandomValues() to fill a random byte array and format it into the standard 8-4-4-4-12 hyphenated structure.

Frequently Asked Questions

Can two generated UUIDs ever be the same?

Theoretically yes, but in practice the probability is so small it is effectively impossible. UUID v4 has 122 bits of randomness, so the odds of a collision across a trillion UUIDs are still around 1 in a billion.

Should I use UUID v4 or v7 for database primary keys?

For modern databases, UUID v7 is increasingly preferred for primary keys because it embeds a timestamp prefix, making rows naturally sortable by insertion order and reducing B-tree index fragmentation. UUID v4 is still fine for non-sequential IDs like session tokens.

Privacy Guaranteed

All data processing, encoding, and formatting are executed locally inside your browser using client-side JavaScript. We never upload your text, inputs, or private data to any server. Your information remains 100% secure.