# Free UUID Generator (v4) Online | Alher Tech

> Generate cryptographically secure UUID v4 identifiers instantly. Create one at a time or in bulk (up to 1000). Copy, export CSV or JSON. 100% client-side.

- Canonical page: https://alhertech.com/en/uuid-generator/
- Site: Alher Tech (custom software, AI agents and SEO engineering, https://alhertech.com/)
- Contact: https://alhertech.com/en/contact/

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Generate cryptographically secure UUIDs (v4) in bulk. Copy or export as CSV / JSON.

Generate cryptographically secure UUID v4 identifiers instantly. Create one at a time or in bulk (up to 1000). Copy, export CSV or JSON. 100% client-side.

## Frequently asked questions

### What is a UUID and when should I use one?

A UUID (Universally Unique Identifier) is a 128-bit identifier designed to be globally unique without a central authority. Use them when you need to generate IDs on the client, merge data from multiple sources, or avoid exposing sequential database IDs.

### Are these UUIDs cryptographically secure?

Yes. The generator uses crypto.randomUUID() which relies on your browser's cryptographically secure random number generator. The probability of collision between two UUIDs is negligible even after generating billions of them.

### What is the difference between UUID v1 and v4?

UUID v1 is based on the MAC address and timestamp, so it can leak information about when and where it was generated. UUID v4 is fully random, which makes it the right default for most use cases because it doesn't leak any information.

### Can I use UUIDs as primary keys in a database?

Yes, but be aware of the tradeoffs. UUIDs are larger than integers (16 bytes vs 4-8), and their randomness can hurt B-tree index performance. For new projects, consider UUIDv7 (time-ordered) if your database supports it.

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