Generator Tools

UUID Generator

Generate valid version 4 UUIDs in your browser — one or up to 100 at once, with uppercase, hyphen and download options. Secure and fully local.

Runs entirely in your browser — nothing you type is uploaded.

This tool runs in your browser. Please enable JavaScript to use it — the guide below explains what it does.

Note: UUIDs are generated in your browser with JavaScript and a secure random generator. With JavaScript off you can read this guide, but the generator controls will not appear.

Generate version 4 UUIDs

This tool generates valid version 4 UUIDs entirely in your browser using crypto.randomUUID() where available, with a standards-compliant fallback built from crypto.getRandomValues(). It never uses Math.random, and nothing is uploaded.

How it works

  1. Choose how many UUIDs you need (1 to 100).
  2. Pick options — uppercase and whether to include hyphens.
  3. Click Generate to produce the UUIDs, one per line.
  4. Copy one, copy all, or download as a text file.

UUID v4 format

A version 4 UUID follows the pattern xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx, where the 4 marks the version and y is one of 8, 9, a or b (the variant). Example: 3f2a7c1e-9b4d-4e6a-8f21-0a1b2c3d4e5f.

Features

  • Secure — uses the browser\'s crypto UUID/ random APIs, never Math.random.
  • Batches — generate up to 100 at once, with no duplicates within a batch.
  • Formatting — uppercase or lowercase, with or without hyphens.
  • Export — copy one, copy all, or download a .txt file.

Limitations

UUID v4 values are randomly generated identifiers. Collisions are extremely unlikely in practice but not mathematically impossible, so this tool does not claim they can never collide.

Privacy

UUIDs are generated locally in your browser. Nothing is uploaded, stored or shared, and the tool makes no network requests.

Frequently Asked Questions

What is a UUID v4?
A UUID (universally unique identifier) is a 128-bit value used to label things uniquely. Version 4 UUIDs are generated from random data and follow the pattern xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx, where the 4 marks the version and y is 8, 9, a or b.
How are they generated?
The tool uses the browser's crypto.randomUUID() when available, with a standards-compliant fallback built from crypto.getRandomValues(). It never uses Math.random, and everything happens locally in your browser.
Can I generate many at once?
Yes — from 1 to 100 UUIDs. Each batch is de-duplicated so there are no repeated values within it, and you get one UUID per line to copy or download as a text file.
Can UUIDs collide?
UUID v4 values are randomly generated identifiers. Collisions are extremely unlikely in practice but not mathematically impossible — this tool does not claim otherwise.
Is anything uploaded or stored?
No. UUIDs are generated locally in your browser. Nothing is uploaded, saved to storage or shared, and the tool makes no network requests.

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