DevToolbox

UUID Generator

Generate, validate, and inspect UUIDs in v4 and v7 formats. Bulk-generate up to 100 at a time.

About This Tool

The UUID Generator creates universally unique identifiers directly in your browser. UUIDs (Universally Unique Identifiers) are 128-bit values used as primary keys, correlation IDs, session tokens, and more. They are designed to be globally unique without requiring a central authority.

This tool supports two UUID versions: Version 4 (random) and Version 7 (time-ordered). UUID v4 uses 122 bits of randomness from the browser's crypto.getRandomValues() API, making collisions astronomically unlikely. UUID v7 embeds a 48-bit Unix millisecond timestamp in the most significant bits, giving UUIDs natural chronological ordering — ideal for database primary keys where insert performance matters.

You can generate a single UUID or bulk-generate 5, 10, 50, or 100 at once. Every UUID can be copied individually, or you can copy all or download the list as a text file. The Validate section lets you paste any string to check whether it is a valid UUID and which version it is. For v7 UUIDs, the embedded timestamp is extracted and displayed.

All generation uses the Web Crypto API and happens entirely client-side. No UUIDs are sent to or stored on any server.

How to Use

  1. Select UUID v4 or UUID v7 using the badges at the top.
  2. Click a generate button (1, 5, 10, 50, or 100) to create UUIDs.
  3. Hover over any UUID and click the copy icon to copy it. Use Copy All or Download for bulk export.
  4. To validate a UUID, paste it into the Validate UUID input. The tool shows whether it is valid and which version it is.
  5. Press Ctrl+Shift+C to copy all generated UUIDs.

FAQ

What is the difference between UUID v4 and v7?

UUID v4 is purely random (122 random bits). UUID v7 encodes a millisecond-precision timestamp in the first 48 bits, followed by random bits. V7 UUIDs sort chronologically, making them better for database indexes.

Can UUIDs collide?

In theory, yes, but the probability is vanishingly small. A UUID v4 has 122 random bits — you would need to generate about 2.7 quintillion UUIDs to have a 50% chance of a single collision.

Are these UUIDs cryptographically secure?

The random bytes are generated using crypto.getRandomValues(), which is a cryptographically secure random number generator. However, UUIDs are not designed to be secret tokens — use a dedicated token generator for that purpose.

When should I use UUID v7?

Use v7 when UUIDs will be used as database primary keys, especially with B-tree indexes. The time-ordered nature of v7 reduces index fragmentation and improves insert performance compared to random v4 UUIDs.

Is my data safe?

Yes. UUID generation happens entirely in your browser using the Web Crypto API. No data is sent to any server.

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