UUID Generator

Generate one or many random v4 UUIDs / GUIDs instantly.

What Does the UUID Generator Do?

This tool generates version 4 UUIDs (Universally Unique Identifiers, also called GUIDs) — 128-bit identifiers like 3f2504e0-4f89-41d3-9a0c-0305e82c3301 built from cryptographically secure random numbers. Generate a single UUID or up to 500 at once, with formatting options: UPPERCASE, hyphen-free, or wrapped in braces ({…}, the style used across the Microsoft ecosystem).

Randomness comes from your browser's crypto API — the same quality source used for encryption keys — so the IDs are suitable for production use.

How to Generate UUIDs

  1. Choose how many UUIDs you need (1–500).
  2. Pick formatting options if needed — changes apply instantly.
  3. Click Generate for a fresh batch.
  4. Copy all with one click or download the list as a .txt file.

Why UUIDs Beat Sequential IDs

  • No coordination needed — any machine can mint IDs independently with effectively zero collision risk, perfect for distributed systems and offline apps.
  • Nothing leaks — sequential IDs reveal record counts and let attackers enumerate resources; random UUIDs do neither.
  • Merge-friendly — combining databases or syncing devices never causes key conflicts.
  • Standardized — RFC 4122 format is understood by every major database, language and framework.

Typical uses: database primary keys, API request IDs, order and transaction references, device identifiers, file names for uploads, and correlation IDs in logs.

Frequently Asked Questions

How unique is a version 4 UUID really?

A v4 UUID contains 122 random bits, giving about 5.3 undecillion possibilities. You would need to generate a billion UUIDs per second for roughly 86 years to reach a 50% chance of a single collision — in practice, treat them as unique.

What do the "4" and the "8/9/a/b" in every UUID mean?

They are fixed by the standard: the third group starts with 4 (version 4 = random) and the fourth group starts with 8, 9, a or b (the RFC 4122 variant bits). The remaining 122 bits are random.

Is there any difference between UUID and GUID?

No — GUID (Globally Unique Identifier) is simply Microsoft's name for the same RFC 4122 UUID format. The braces option produces the registry-style {GUID} notation used on Windows.

Are these UUIDs safe for production databases?

Yes. They are generated with the cryptographically secure crypto.getRandomValues API (or crypto.randomUUID where available), the same approach production libraries use.