ToolKitly

UUID Generator

Generate cryptographically random UUID v4 values - one at a time or 500 at once. Formatting options cover the variants used by databases, C# and JSON APIs.

Between 1 and 500.

Format
0 UUID

All processing happens in your browser. Files are never uploaded to a server.

At a glance

Processing
In your browser - nothing is uploaded
Price
Free, no account

How to use

  1. Choose how many UUIDs you need.

  2. Pick formatting options: uppercase, hyphens, braces.

  3. Click "Generate UUIDs".

  4. Copy the whole list.

Frequently asked questions

Are these UUIDs cryptographically random?

Yes. They come from the browser crypto API, the same source used for cryptographic keys - not from Math.random, which is predictable and unsuitable for identifiers that must not collide or be guessable.

What is a UUID v4?

Version 4 means the identifier is generated from random data rather than from a timestamp or MAC address. It has 122 random bits, with the remaining 6 fixed to mark the version and variant.

Can two UUIDs ever be the same?

In theory yes, in practice no. With 122 random bits you would need to generate about 2.7 quintillion UUIDs before a 50% chance of a single collision. For any real application the risk is negligible.

Should I use a UUID as a database primary key?

It works and avoids coordinating IDs across services, but random UUIDs scatter inserts across the index, which hurts write performance on large tables. If that matters, look at time-ordered alternatives such as UUID v7 or ULID.

Why would I remove the hyphens or add braces?

Different ecosystems expect different formats. Braces are the Microsoft/C# registry style, hyphen-free strings are common in URLs and compact storage, and uppercase appears in some legacy systems.

Are the generated UUIDs sent anywhere?

No. They are generated in your browser and never transmitted or logged.

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