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May 26, 2026 · numbers · 3 min read

Best UUID Generator Tools

A practical look at UUID versions, when each one matters, and what to look for in a generator you can trust for production use.

What a UUID actually is

A UUID (Universally Unique Identifier) is a 128-bit value, usually written as 32 hex characters in 5 groups: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx. The point of the format is that two parties can independently generate IDs without coordinating, and the odds of collision are vanishingly small.

There isn't one UUID — there are several versions, and the right one depends on what you're doing.

The versions that matter

  • UUID v4 (random). 122 random bits. The default for almost any general-purpose ID — session tokens, primary keys you don't need to sort by time, anything where uniqueness is the only requirement.
  • UUID v7 (time-ordered). Embeds a millisecond timestamp at the front, then random bits. Sortable by creation time, much better for database primary keys because rows land close together on disk.
  • UUID v1 (MAC + time). Older time-based version that leaks the generating machine's MAC address. Generally avoid in 2026.
  • UUID v5 (namespaced hash). Deterministic — same inputs always produce the same UUID. Useful when you need a stable ID derived from existing data.

If you don't have a specific reason, v4 for general use, v7 if you need time-sortable IDs.

What to look for in a generator tool

  • Bulk mode. You almost never need exactly one. A tool that gives you 100 at once saves time.
  • Format options. With/without hyphens, uppercase, Base64 variants.
  • Multiple versions. Especially v4 and v7, since they cover most modern needs.
  • No tracking, no signup. UUIDs aren't sensitive on their own, but you shouldn't have to hand over an email to generate one.

When you should generate them in code instead

Online tools are great for one-off needs and bulk testing data. For production code, use your platform's native UUID library — crypto.randomUUID() in modern Node and browsers, uuid package for v7, uuid_generate_v4() in Postgres, and so on. Don't paste IDs from a web tool into a running system.

Try our UUID Generator for development, testing, and seed data.

A few generators that pair well with the topics above: