UUID Generator

A UUID (Universally Unique Identifier) is a 128-bit value written as 32 hex digits in five hyphen-separated groups, like 550e8400-e29b-41d4-a716-446655440000. Two systems can each generate IDs independently and still avoid collisions in practice. UUIDs appear as primary keys in databases, file identifiers, and event tracking IDs.

v4 uses 122 random bits after version and variant fields. v7 starts with a 48-bit Unix-millisecond timestamp and uses the remaining fields for version, variant, and random data, so IDs sort roughly by creation time. Use either as an identifier. Use a purpose-built secret-token generator for sessions or bearer credentials.

Collision probability follows the birthday bound over 122 random bits. At one billion UUIDs per second for 100 years, the chance is about 61%, not negligible. Ordinary application volumes are far lower, but a database should still enforce uniqueness and retry on conflict rather than assume collisions are impossible.

The implementation uses Web Crypto for v4 and the random portion of v7, but UUID format is designed for identification, not authentication. Do not treat these values as session tokens, password-reset links, API keys, or secret keys. Use a purpose-built token with an explicit security requirement.

Yes. The validator accepts hyphenated, unhyphenated, braced, lowercase, uppercase, and mixed-case input. It strips outer braces, removes hyphens, checks that all 32 characters are valid hex, then verifies the version digit (position 14) and the variant bits (position 19 must be 8, 9, a, or b). A passing input returns the canonical lowercase form and the detected version number.