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v4

Random UUID Generator

100% Free

Generate cryptographically random UUIDs (v4), time-ordered UUIDs (v7), or the nil UUID — with uppercase and no-hyphen options, in bulk, right in your browser.

Crypto-Random
v4 + v7 + Nil
Bulk + Copy
100% Client-Side
UUID format

1 to 1000 at a time.

Generated UUIDs
Press Generate to create UUIDs — they'll appear here.

UUIDs are generated locally with your browser's crypto API — nothing is sent to a server.

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<iframe
  src="https://tools.town/embed/uuid-generator-security/"
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  loading="lazy"
  title="Random UUID Generator">
</iframe>

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How to Use

  1. 1 Pick a UUID format — v4 (random), v7 (time-ordered), or the nil UUID
  2. 2 Set how many you need, from 1 up to 1000 at a time
  3. 3 Toggle uppercase and hyphens to match the format your system expects
  4. 4 Press Generate to create the UUIDs instantly in your browser
  5. 5 Copy a single UUID with its row button, or use Copy all for the whole list

Features

  • Generates RFC 9562 version 4 (random) UUIDs with correct version and variant bits
  • Generates version 7 (time-ordered) UUIDs that sort by creation time — ideal for database keys
  • Outputs the nil UUID (all zeros) when you need a placeholder identifier
  • Bulk generation of up to 1000 UUIDs in a single click
  • Uppercase and hyphen-free formatting options for any downstream system
  • Uses the browser's crypto.getRandomValues — random values never leave your device

Why it Matters

A UUID is a 128-bit identifier with so many possible values that two independently generated ones practically never collide. That property lets distributed systems, databases, and APIs create unique keys without coordinating with a central server. Generating them with a cryptographically strong random source — rather than a weak Math.random — is what keeps v4 UUIDs genuinely unpredictable and collision-resistant.

★★★★★

Use Cases

Database Primary Keys

Use v7 UUIDs as time-ordered keys that index well and avoid auto-increment leaks

API Request IDs

Tag each request with a unique v4 UUID for tracing and idempotency

Test & Seed Data

Generate hundreds of unique identifiers in bulk for fixtures and load tests

File & Object Names

Create collision-free names for uploads, exports, and temporary objects

What this tool does

The Random UUID Generator creates universally unique identifiers right in your browser. Choose the format you need — v4 for fully random IDs, v7 for time-ordered IDs, or the nil UUID for an all-zero placeholder — set how many you want, and copy them out one at a time or all at once. The random bytes come from your browser’s crypto.getRandomValues, so the values are cryptographically strong and never leave your device.

UUID versions

  • Version 4 (random): Every bit that isn’t fixed is random. v4 is the everyday choice for IDs you don’t want anyone to guess — request IDs, session tokens, object names.
  • Version 7 (time-ordered): A 48-bit millisecond timestamp leads the value, followed by random bits. Because the timestamp comes first, v7 UUIDs sort by creation time, which keeps database index inserts sequential and friendly to B-tree storage.
  • Nil: The reserved all-zero UUID, useful as an explicit “no value” sentinel or a stable value in tests.

Privacy

Everything runs locally. The UUIDs you generate are produced in your browser with the native crypto API and are never uploaded, logged, or stored.

Frequently Asked Questions

What is a UUID?
A UUID (Universally Unique Identifier), sometimes called a GUID, is a 128-bit value usually written as 32 hexadecimal digits in five hyphen-separated groups, like 123e4567-e89b-12d3-a456-426614174000. The space of possible values is so vast that two randomly generated UUIDs are astronomically unlikely to ever collide, which is why they're used as unique keys without any central coordinator.
What's the difference between UUID v4 and v7?
Version 4 is fully random — every UUID is independent and unpredictable, which is great for identifiers you don't want anyone to guess. Version 7 puts a millisecond timestamp at the front and fills the rest with random bits, so v7 UUIDs naturally sort in the order they were created. That time-ordering makes v7 a better fit for database primary keys because it keeps index inserts sequential.
Are these UUIDs cryptographically secure?
Yes. This tool generates the random bytes with your browser's crypto.getRandomValues, the same cryptographically strong source used for security-sensitive values. That makes v4 UUIDs genuinely unpredictable, unlike generators that rely on Math.random. Note that v7 still embeds a timestamp by design, so it is time-ordered rather than secret.
Is the nil UUID useful for anything?
The nil UUID — 00000000-0000-0000-0000-000000000000 — is a special all-zero value defined by the spec. It's handy as an explicit placeholder, a default 'no value' sentinel in a UUID column, or a known value in tests where you don't want a random one each run.
Is this tool free, and is anything sent to a server?
It's completely free with no sign-up, and nothing is sent anywhere. Every UUID is generated locally in your browser using the built-in crypto API, so the values never touch a network or a server log.
📖

Want to learn how this works?

Browse all guides →
UUIDs Explained
uuid

UUIDs Explained: v4, v7, and When to Use Each

Learn what a UUID is, how the 128-bit format works, the difference between v4 and v7, why cryptographic randomness matters, and how to choose the right version.

25 Jun 2026

5 min read

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