ToolSink

UUID Generator

Generate cryptographically-random RFC 4122 v4 UUIDs in bulk.

What is the UUID Generator?

The UUID Generator produces cryptographically-strong version 4 UUIDs — 128-bit random identifiers that are, for all practical purposes, guaranteed to be unique across the world. They are the standard choice for primary keys, request IDs, correlation IDs and API tokens.

The tool can generate a single UUID at a click or a batch of hundreds ready to paste into a database seed script or a testing fixture. It also formats each UUID with or without dashes and in upper or lower case, depending on the destination system.

UUID generation is a pure client-side operation using the browser’s cryptographic random source, so the IDs never travel through any server and cannot be replayed against you.

How to use the UUID Generator

  1. 1Open the UUID Generator page.
  2. 2Choose how many UUIDs you need (1, 10, 100 or a custom number).
  3. 3Pick formatting options: with or without dashes, uppercase or lowercase.
  4. 4Click "Generate".
  5. 5Copy the whole list with one click or download as .txt / .csv.

Key features

  • RFC 4122 version-4 (random) UUIDs
  • Batch generation up to thousands at once
  • Uppercase, lowercase, dash-less variants
  • Copy all or download as file
  • Cryptographically random source
  • Runs offline in the browser

Examples

Single UUID

Output
b6e5f9a2-4d84-4e37-8f5f-1e6c1a3fd8f9

Batch of five

Output
9d1a7c04-9b12-4b53-9fdd-2b5b1b9e91c7
fc5a2d70-9f1e-46f7-b7ba-6b6c9d0e0f19
1c96b1af-84cf-4b70-8d69-6b0b2a8b7912
5e8f83d5-6d16-4c9c-a8d2-fd4a5f26b03b
5f2a3d31-3f1b-4b12-8e2e-4bbd4b2e2fbb

Uppercase, no dashes

Output
B6E5F9A24D844E378F5F1E6C1A3FD8F9

Why use this tool

  • Guarantees unique identifiers for distributed systems
  • No coordination with a central server
  • Batch generation saves manual work
  • Random source is cryptographically secure
  • Free and unlimited

Common use cases

  • Primary keys in NoSQL databases
  • Correlation IDs for distributed tracing
  • API request IDs
  • File names to avoid collisions
  • One-time invite tokens
  • Test fixture identifiers

Frequently asked questions

Are the UUIDs really unique?

Version 4 UUIDs have 122 random bits. Collisions are astronomically unlikely — one in trillions of trillions.

Can I generate v1 (time-based) UUIDs?

Only v4 is currently supported. Time-based v7 support is on the roadmap.

How random are they?

The tool uses the Web Crypto API which provides cryptographically-secure randomness.

Do you ever see the UUIDs?

No — they are generated inside your browser tab and never leave your device.

What is the maximum batch size?

You can generate tens of thousands at a time. Very large batches may take a second to render.