Free tool

UUID Generator Online

Generate unique UUID v4 with crypto.randomUUID(). Bulk generation, history. No sign-up.

Generate
UUID v4 · 128 bits · Generated with crypto.randomUUID() · 100% in browser

Click "Generate UUID" to start

Built by

Miguel Ángel Colorado Marin

Full-Stack Developer · Guadalajara, España

I develop web apps, digital tools and full projects — from design to deployment.

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How to use the UUID generator?

  1. 1

    Generate a single UUID

    Click the «Generate UUID» button to create a random UUID v4 instantly. Each UUID is unique thanks to the browser's native crypto.randomUUID() API, which guarantees 122 bits of cryptographic randomness.

  2. 2

    Generate multiple UUIDs at once

    Enter the number of UUIDs you want to generate (between 1 and 100) in the number field and click the «at once» button. All will be added to the history instantly.

  3. 3

    Copy the UUID you need

    Each UUID in the history has its own copy button. Clicking it automatically copies the UUID to your clipboard with visual confirmation. The history keeps up to 30 UUIDs.

  4. 4

    Copy all or clear the history

    Use the «Copy all» button to export all generated UUIDs at once (one per line), ideal for inserting them into databases or configuration files. The «Clear» button empties the history.

Frequently asked questions

What is a UUID?

UUID (Universally Unique Identifier) is a 128-bit identifier standardized by RFC 4122. It is represented as 32 hexadecimal digits in the format 8-4-4-4-12, e.g.: 550e8400-e29b-41d4-a716-446655440000. They are used as primary keys in databases, session identifiers, tokens, etc.

What is UUID v4 and why use it?

UUID v4 is the most popular version: it generates 122 completely random bits. The probability of collision is extremely low (you would need to generate billions of UUIDs to have a 1% probability of collision). It is the standard format for unique identifiers in modern applications.

Is crypto.randomUUID() secure?

Yes. The crypto.randomUUID() API uses the operating system's cryptographically secure random number generator (CSPRNG), the same one used to generate cryptographic keys. It is more secure than Math.random() and is available in all modern browsers.

What is the difference between UUID and ULID?

UUID v4 is completely random and not sortable. ULID (Universally Unique Lexicographically Sortable Identifier) includes a time component that makes it lexicographically sortable, improving database index performance. For most use cases, UUID v4 is sufficient.

Are my generated UUIDs saved?

No. The UUID history only exists in browser memory while the page is open. Upon reload or closing the tab, the history is automatically cleared. No data is ever sent to any server.

Embed the generator on your site

Embed this UUID generator in any web page with a simple iframe:

<iframe
  src="https://miguelacm.es/embed/uuid-generator"
  width="100%"
  height="600"
  frameborder="0"
  title="UUID Generator"
></iframe>
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View source on GitHub