About This Site

Last updated: July 26, 2026

What This Site Is

This is a free, developer-focused UUID generator that supports all eight UUID versions defined in RFC 4122 (2005) and RFC 9562 (May 2024). Every UUID is generated entirely in your browser using the Web Crypto API — nothing is sent to any server, logged, or stored.

Built for developers who need accurate, RFC-compliant UUIDs without signing up for anything, installing anything, or trusting a third-party server with their data.

Why We Built This

UUID generation sounds simple, but most online tools get at least one thing wrong: they serve old v4-only generators without explaining the difference between versions, have no v6 or v7 support despite RFC 9562 shipping in May 2024, transmit values to a server (defeating the point of client-side generation), or bury the tool under ads and unnecessary friction.

We built this to be the reference-quality UUID tool we wished existed: one that covers all eight versions, cites the actual RFCs, explains when to use each version, and puts the tool front and center with no signup, no tracking of generated values, and no server round-trips.

UUID Version Coverage

This tool generates all UUID versions defined in both RFC 4122 and the newer RFC 9562:

  • v1 — Timestamp + MAC address (RFC 4122)
  • v3 — Name-based with MD5 hash (RFC 4122)
  • v4 — Random (RFC 4122) — general purpose default
  • v5 — Name-based with SHA-1 hash (RFC 4122)
  • v6 — Time-ordered, field-compatible v1 upgrade (RFC 9562)
  • v7 — Unix millisecond timestamp + random; recommended for database primary keys (RFC 9562)
  • v8 — Custom layout for implementation-defined schemas (RFC 9562)
  • Nil / Max — Special sentinel values (RFC 9562)

Technical Standards

All UUIDs conform to their respective RFC specifications. The random number generator used for v4, v7, and v8 is crypto.getRandomValues() — the browser’s cryptographically secure pseudo-random number generator (CSPRNG). SHA-1 hashing for v5 uses the browser’s native crypto.subtle.digest() API.

Privacy First

No UUID you generate here is ever seen by us. The tool runs entirely in your browser. There is no backend API call, no analytics on specific values generated, and no clipboard access beyond what you explicitly trigger by clicking Copy. You can verify this yourself by opening your browser’s Network tab — you will see zero outbound requests when you click Generate.

What the Site Covers

Beyond the generator tool, this site provides developer reference content covering:

  • Version-by-version explanations with RFC citations and bit-layout details
  • Code examples across Python, JavaScript, Go, Java, PHP, Rust, and more
  • Database-specific generation guides for PostgreSQL, MySQL, MongoDB, and SQL Server
  • The v4 vs v7 primary key debate and B-tree index locality
  • UUID vs ULID, NanoID, CUID2 comparison
  • UUID validation patterns, format anatomy, and collision probability

Advertising

This site is free to use and supported by display advertising served through Google AdSense. Ads never influence our technical content, recommendations, or tool functionality. We do not accept sponsored placements or paid promotions in our editorial content.

Get in Touch

Found a bug? Have a suggestion? Want to report incorrect technical information? We are happy to hear from developers. Please use the Contact page.