Generate universally unique identifiers (UUIDs) — v1 (time-based), v4 (random), and v5 (name-based). 100% offline, no signup, unlimited generation.
Uses the current timestamp + MAC address. Unique across space and time but not recommended for privacy (MAC address may leak).
Generated from cryptographically secure random values. The most common UUID version, used everywhere from databases to APIs.
Deterministic: same name + namespace always produces the same UUID. Useful for generating stable IDs from URLs, emails, or file paths.
A UUID (Universally Unique Identifier) is a 128-bit label used to uniquely identify information. The probability of generating two identical v4 UUIDs is astronomically small.
For most purposes, use v4. It's random, safe, and supported everywhere. Use v5 if you need deterministic IDs (same input = same output). Avoid v1 unless you have a specific reason — it can leak your MAC address.
Yes. v4 UUIDs are generated using crypto.getRandomValues() — the same cryptographic random source used by security software.
A namespace is a fixed UUID used as the "prefix" for name-based generation. The standard namespaces (DNS, URL, OID, X.500) are predefined by RFC 4122.
No. All generation happens locally in your browser. Nothing is stored, logged, or transmitted.