UUID Generator

Generate random v4 UUIDs, time-ordered v7 UUIDs, or a nil UUID — one or thousands at a time, with a cryptographic random source in your browser.

🔒 Runs entirely in your browser — nothing you type is uploaded or stored on a server.

The UUID Generator creates universally unique identifiers — the 128-bit values (also called GUIDs) used as primary keys, request IDs, file names and de-duplication tokens across databases and distributed systems. Generate a single UUID or a bulk batch of up to a thousand at once, then copy or download the list. The default is the ubiquitous version 4 (fully random) format like 3f2504e0-4f89-41d3-9a0c-0305e82c3301.

Randomness comes from your browser's cryptographically secure generator (crypto.getRandomValues), and the version and variant bits are set exactly as the spec requires, so every ID is a valid, standards-compliant UUID. A v4 UUID has 122 random bits — the odds of two ever colliding are astronomically small, which is why they're safe to generate independently on any machine without coordination.

You can also generate version 7 UUIDs, a newer format that embeds a millisecond timestamp at the front so the IDs sort in creation order — ideal as database keys because they keep indexes tidy while staying unique. A nil UUID (all zeros) is available for placeholders and tests. Format the output your way with uppercase, hyphen and brace toggles. It all runs in your browser — nothing is generated on or sent to a server.

How to use

  1. Choose a version: v4 (random) for general use, v7 (time-ordered) for sortable database keys, or Nil for a placeholder.
  2. Set how many you need — from one to a thousand.
  3. Toggle formatting: uppercase, hyphens on/off, or wrap each in braces { }.
  4. Click Generate UUID.
  5. Copy the list or download it as a .txt file.

Examples

A single v4 UUID
Get one random identifier like 3f2504e0-4f89-41d3-9a0c-0305e82c3301 for a record, request or file.
Bulk generation
Set the quantity to 500 to seed test data or pre-generate a batch of keys, then download them all at once.
Sortable keys (v7)
Choose version 7 so the UUIDs embed a timestamp and sort in creation order — friendlier for database indexes than fully random v4.
Formatting
Turn off hyphens and switch on uppercase for systems that expect a compact 32-character form, or add braces for Microsoft-style GUIDs.

Frequently asked questions

What is a UUID (or GUID)?
A Universally Unique Identifier is a 128-bit value written as 32 hexadecimal digits in five hyphen-separated groups. GUID is Microsoft's name for the same thing. They're used as unique keys, IDs and tokens that can be created independently anywhere without collisions.
What's the difference between v4 and v7?
Version 4 is fully random — simple and unpredictable, the most common choice. Version 7 puts a millisecond timestamp at the start followed by random bits, so IDs generated over time sort in creation order. v7 is often better as a database primary key because it keeps indexes sequential.
Are these UUIDs really unique?
For practical purposes, yes. A v4 UUID has 122 random bits generated from a cryptographic source, so the chance of a collision is vanishingly small — you would need to generate billions per second for centuries to have any realistic risk.
Are they generated securely and privately?
Yes. They use your browser's cryptographic random number generator (crypto.getRandomValues) and are created entirely on your device. Nothing is requested from or sent to a server.
Can I generate many at once?
Yes — up to 1,000 per batch. That's handy for seeding test databases, pre-allocating keys, or creating a pool of tokens. Copy them all or download the list as a text file.
What is the nil UUID?
The nil UUID is all zeros (00000000-0000-0000-0000-000000000000). It's a special value used as a placeholder, default, or “no ID” marker in code and tests.

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