Util Hub.io

UUID Generator (v4)

Generate random UUID v4 identifiers in bulk. RFC 4122 compliant, client-side, no signup.

10 Generated

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Free Online UUID Generator — v4, Bulk & Client-Side

Generate cryptographically random UUID v4 identifiers with one click — single or up to 500 in bulk. UtilHub's UUID generator produces RFC 4122-compliant identifiers for database primary keys, session tokens, request IDs, file names, and any distributed system that needs guaranteed uniqueness without a central authority. Every ID is generated locally via the Web Crypto API (the same secure source operating systems use), so values never leave your machine. Toggle hyphens, switch case, and copy individual or all IDs with a single click. Unlike most online UUID generators, nothing is logged or sent to a server — verifiable by going offline after page load.

How to use UUID Generator (v4)

  • Click "Generate UUID" to create a new identifier.
  • Adjust the quantity slider for bulk generation (up to 500 at once).
  • Toggle hyphens, uppercase/lowercase, and braces to match your format.
  • Click "Copy" next to a single UUID or "Copy All" for the whole list.
  • Click "Regenerate" to roll a fresh batch with the same settings.

Features

  • RFC 4122 compliant — Generates version 4 UUIDs using the Web Crypto API for true randomness, not pseudo-random Math.random().
  • Bulk generation — Generate up to 500 UUIDs at once. Perfect for seeding databases, test data, or migration scripts.
  • Format options — Output with or without hyphens, uppercase or lowercase. Match whatever format your system expects.
  • Zero duplicates, fully private — 2¹²² possibilities makes collisions practically impossible, and nothing is sent to a server.

Frequently Asked Questions

What is a UUID v4 and when should I use it?

A UUID v4 (Universally Unique Identifier, version 4) is a 128-bit identifier generated from random numbers. It looks like <code>550e8400-e29b-41d4-a716-446655440000</code>. Use UUID v4 whenever you need a unique ID without coordinating with a central database — common use cases include database primary keys, API request IDs, file names, and distributed system identifiers.

Are the UUIDs generated here truly random and secure?

Yes. This tool uses the Web Crypto API (<code>crypto.getRandomValues()</code>), which provides cryptographically strong random numbers from your operating system's entropy pool. This is far more secure than <code>Math.random()</code>, which many online UUID generators still use — and the IDs never leave your browser.

What is the difference between UUID v4, v1, and v7?

UUID v4 is purely random — best for general-purpose unique IDs. UUID v1 embeds a timestamp and MAC address; it sorts chronologically but can leak identifying info. UUID v7 (newer) embeds a Unix timestamp and is great for database indexes because it sorts naturally by creation time, improving B-tree performance. Most applications today use v4 for safety and simplicity; switch to v7 if database insert order matters.