UUID Generator

A UUID (Universally Unique Identifier) is a 128-bit label used to uniquely identify objects in computer systems. Standardized by RFC 4122, they are represented as 32 hexadecimal digits in the form xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx, where M denotes the version and N the variant.

v4 (random) is the right choice for almost every use case. It contains no embedded information about the host or time, maximizing privacy and security. v1 (time-based) embeds the current timestamp and a node identifier — useful when sortability by creation time matters, but leaks timing and potentially MAC address information. For database primary keys, tokens, or session IDs: always use v4.

Yes. This tool uses crypto.randomUUID() (or crypto.getRandomValues() as fallback), both backed by the browser's CSPRNG — the same source as /dev/urandom on Linux. They are safe to use as tokens, keys, and identifiers in security-sensitive contexts.

Theoretically yes, but practically no. A UUID v4 has 122 bits of randomness (~5.3 × 10³⁶ possible values). The probability of a collision between two randomly generated UUIDs is vanishingly small — roughly the probability of winning the lottery three times in a row. In practice, UUID v4 collision is treated as impossible.

No. All UUID generation happens entirely in your browser using the Web Crypto API. No data is transmitted anywhere. This page works fully offline once loaded.