TOOLADEX

UUID Generator

Generate UUID v4 (random UUIDs) instantly. Perfect for unique identifiers in databases, APIs, distributed systems, and any application requiring unique IDs.

100% Client-Side Generation

UUIDs are generated entirely in your browser using cryptographic randomness. No data is sent to any server.

Generate 1 to 1000 UUIDs at once. Perfect for database seeding, batch processing, or testing.

Table of Contents

What is a UUID?

A **UUID (Universally Unique Identifier)** is a 128-bit identifier that's designed to be unique across time and space. UUIDs are standardized by RFC 4122 and are commonly used in distributed systems, databases, APIs, and applications where unique identifiers are required.

UUIDs are typically represented as 32 hexadecimal digits displayed in five groups separated by hyphens, in the format: `xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx`. For example: `550e8400-e29b-41d4-a716-446655440000`.

The probability of generating duplicate UUIDs is extremely low (approximately 1 in 2^122 for UUID v4), making them suitable for use as unique identifiers without coordination between different systems.

UUID Versions

There are several versions of UUIDs, each with different characteristics and use cases:

UUID v4 (Random UUID)

UUID v4 is the most commonly used version. It's generated using random or pseudo-random numbers, making it ideal for most applications where uniqueness is the primary concern.

Characteristics:

  • Generated using random numbers
  • No information about when or where it was created
  • Extremely low collision probability
  • Most widely used and recommended for general purposes

Use cases: Database primary keys, API identifiers, session IDs, transaction IDs, resource identifiers

UUID v1 (Time-based UUID)

UUID v1 incorporates the current timestamp and the machine's MAC address (or a random node ID), making it possible to extract the creation time from the UUID.

Characteristics:

  • Includes timestamp information
  • Can be sorted chronologically
  • Contains MAC address (can be privacy concern)
  • Less commonly used than v4

Use cases: Distributed systems requiring chronological ordering, logging systems

Other UUID Versions

Other UUID versions (v2, v3, v5, v6, v7, v8) exist but are less commonly used. Our generator focuses on UUID v4, which is the most widely adopted and recommended version for most use cases.

How it Works

Our UUID Generator uses cryptographic randomness to generate UUID v4 identifiers:

  • Cryptographic Randomness: Uses the browser's `crypto.randomUUID()` API or `crypto.getRandomValues()` for secure random number generation
  • UUID v4 Format: Generates UUIDs following the RFC 4122 specification for version 4
  • Client-Side Generation: All UUIDs are generated entirely in your browser — no server requests
  • Instant Generation: UUIDs are generated instantly without delays or waiting
  • Batch Generation: Generate multiple UUIDs at once (up to 1000) for efficiency
  • Copy Functionality: Copy individual UUIDs or all UUIDs to clipboard with one click

The generator automatically creates new UUIDs when you change the count, and provides easy copy functionality for integrating UUIDs into your projects.

Common Use Cases

  • Database Primary Keys: Use UUIDs as primary keys in databases to avoid ID conflicts in distributed systems
  • API Identifiers: Generate unique identifiers for API resources, endpoints, and requests
  • Session Management: Create unique session IDs for user authentication and tracking
  • Distributed Systems: Generate unique IDs across multiple services without coordination
  • File Naming: Create unique filenames to avoid conflicts when storing files
  • Transaction IDs: Generate unique transaction identifiers for payment systems and financial applications
  • Testing & Development: Generate test data, mock IDs, and sample identifiers for development
  • Database Seeding: Generate multiple UUIDs for populating databases with test data
  • Resource Identifiers: Create unique identifiers for resources in REST APIs and web services
  • Event Tracking: Generate unique event IDs for analytics and logging systems

Examples

Example 1: Database Primary Key

Use UUIDs as primary keys in your database tables:

CREATE TABLE users (
  id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
  username VARCHAR(50),
  email VARCHAR(100)
);

-- Or insert with explicit UUID
INSERT INTO users (id, username, email) VALUES (
  '550e8400-e29b-41d4-a716-446655440000',
  'johndoe',
  'john@example.com'
);

Example 2: API Resource Identifier

Use UUIDs as resource identifiers in REST APIs:

GET /api/users/550e8400-e29b-41d4-a716-446655440000
POST /api/orders
{
  "id": "7c9e6679-7425-40de-944b-e07fc1f90ae7",
  "userId": "550e8400-e29b-41d4-a716-446655440000",
  "total": 99.99
}

Example 3: JavaScript/Node.js

Generate UUIDs in JavaScript applications:

// Using crypto.randomUUID() (Node.js 14.17+, modern browsers)
const uuid = crypto.randomUUID();
console.log(uuid); // e.g., "550e8400-e29b-41d4-a716-446655440000"

// Using in an object
const user = {
  id: crypto.randomUUID(),
  name: 'John Doe',
  email: 'john@example.com'
};

Example 4: Database Seeding

Generate multiple UUIDs for database seeding:

-- Generate 10 UUIDs for test users
INSERT INTO users (id, username, email) VALUES
  ('550e8400-e29b-41d4-a716-446655440000', 'user1', 'user1@example.com'),
  ('6ba7b810-9dad-11d1-80b4-00c04fd430c8', 'user2', 'user2@example.com'),
  ('6ba7b811-9dad-11d1-80b4-00c04fd430c8', 'user3', 'user3@example.com'),
  -- ... more users
;

Frequently Asked Questions

What is UUID v4?

UUID v4 (version 4) is a randomly generated UUID. It's the most commonly used UUID version and is generated using random or pseudo-random numbers. UUID v4 doesn't contain any information about when or where it was created, making it ideal for most applications where uniqueness is the primary concern.

How unique are UUIDs?

UUID v4 has an extremely low collision probability — approximately 1 in 2^122 (or about 1 in 5.3 × 10^36). This means the chance of generating duplicate UUIDs is negligible for practical purposes. Even if you generated 1 billion UUIDs per second, it would take approximately 85 years to have a 50% chance of generating one duplicate.

Are UUIDs secure?

UUID v4 uses cryptographic randomness, making them suitable for use in security-sensitive applications. However, UUIDs themselves are not encrypted or hashed — they're just unique identifiers. Don't use UUIDs as security tokens or passwords. They're designed for uniqueness, not secrecy.

Can I generate multiple UUIDs at once?

Yes! You can generate 1 to 1000 UUIDs at once. This is perfect for database seeding, batch processing, testing, or any scenario where you need multiple unique identifiers. Simply adjust the "Number of UUIDs" input and click generate.

Is my data sent to a server?

No. All UUID generation happens entirely in your browser using the browser's cryptographic APIs. Your data is never sent to any server, ensuring complete privacy and security.

What's the difference between UUID v1 and v4?

UUID v1: Time-based UUID that includes timestamp and MAC address information. Can be sorted chronologically but contains potentially sensitive information.

UUID v4: Randomly generated UUID with no embedded information. Most widely used, recommended for general purposes, and provides better privacy since it doesn't contain any identifying information.

Can I use UUIDs as database primary keys?

Yes! UUIDs are commonly used as primary keys in databases, especially in distributed systems. However, be aware that UUIDs are larger (16 bytes) than integer IDs (4-8 bytes) and may have performance implications for very large tables or indexes. Many databases have native UUID support with optimized storage.

How do I validate a UUID?

UUIDs follow a specific format: 32 hexadecimal digits displayed in five groups separated by hyphens: `xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx`. You can validate UUIDs using regular expressions or UUID validation libraries. Most programming languages have UUID validation functions in their standard libraries.

Can UUIDs be sorted?

UUID v4 (random UUIDs) cannot be meaningfully sorted since they're randomly generated. UUID v1 (time-based UUIDs) can be sorted chronologically since they contain timestamp information. If you need sortable unique IDs, consider UUID v1 or using ULIDs (which are lexicographically sortable).

What browsers support UUID generation?

Modern browsers (Chrome 92+, Firefox 95+, Safari 15.4+, Edge 92+) support the native `crypto.randomUUID()` API. Our generator also includes a fallback method using `crypto.getRandomValues()` for older browsers, ensuring UUID generation works across all modern browsers.