FAQ
UUID v4 is purely random (122 random bits), offering maximum unpredictability. UUID v7 (defined in RFC 9562) combines a 48-bit Unix timestamp in milliseconds with random bits, making it time-ordered (lexicographically sortable) and vastly more efficient for database primary keys and B-tree indexing.
Yes. Random bits in v4, v7, and v1 are generated using window.crypto.getRandomValues(), a browser implementation of cryptographically secure pseudo-random number generators (CSPRNG).
UUID v3 (MD5) and UUID v5 (SHA-1) generate deterministic UUIDs based on a Namespace UUID and an input string (e.g. domain name or URL). The same namespace and name will always yield the exact same UUID output.
A NIL UUID is a special case UUID where all 128 bits are set to zero (00000000-0000-0000-0000-000000000000). It is often used as a placeholder or default value in data structures.
No. All generation and parsing logic runs 100% client-side inside your browser JavaScript runtime. Your generated keys and input strings never leave your machine.