UUID Generator
Generate Universally Unique Identifiers (UUIDs) in batches. Supports UUID v1 (time-based) and v4 (random) with multiple formatting options & programming examples.
UUID Configuration
Generated Results
Click «Generate UUIDs» to start
Quick Presets
What is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit number used to uniquely identify information in computer systems. The probability of generating duplicate UUIDs is so low that they can be considered unique without requiring a central authority. UUIDs are standardized by RFC 4122 and are widely used in distributed systems, databases, and software applications for creating unique identifiers.
UUID v1 versus v4
UUID v1 uses a MAC address and a timestamp to build each value. This mix gives strong uniqueness across space and time. It also carries traceable details, which helps with record tracking but reduces privacy. Some developers use UUID v1 for primary keys because the order of creation stays clear and predictable.
How UUID v4 Works
UUID v4 uses random or pseudo random numbers to create each value. It holds no traceable details, which protects privacy and security. It has become the most common version in modern systems. The random nature keeps each value unpredictable and easy to use across large applications.
Pros of UUID v1 and v4
UUID v1 gives clear order because each value reflects a real timestamp. This helps when sorting large records or tracking events. It also pulls in the MAC address, which keeps each value unique across devices. UUID v4 shines in simple setups. It uses random numbers and skips all hardware details. This makes it clean, private, and easy to use in any system.
Cons of UUID v1 and v4
UUID v1 exposes traceable details, including the MAC address and the creation time. This creates privacy concerns in some projects. It also grows more predictable, which reduces security in sensitive systems. UUID v4 has its own limits. It removes time information, so sorting by creation order becomes harder. It also depends on strong random sources to keep values safe from patterns.
Where These UUIDs Are Used
Developers use UUIDs in many places. Database primary keys use them to keep each record safe from conflicts. API request IDs help track calls across systems. Session tokens support user logins. File names stay unique across storage systems. Distributed systems use them to assign IDs across many servers. Message queues use them to track events, and transaction systems use them to label each action.
How to generate UUIDs in different programming languages
| Language | How to generate UUID |
|---|---|
| JavaScript | import { v4 as uuidv4 } from 'uuid';
const id = uuidv4(); Generate UUID v4 using uuid library |
| Python | import uuid
id = str(uuid.uuid4()) Generate UUID using Python's built-in uuid module |
| Java | import java.util.UUID;
String id = UUID.randomUUID().toString(); Generate UUID using Java's built-in UUID class |
| C# | using System;
string id = Guid.NewGuid().ToString(); Generate GUID using .NET's Guid class |
| PHP | function guidv4() {
return sprintf('%04x%04x-%04x-%04x-%04x-%04x%04x%04x',
mt_rand(0, 0xffff), mt_rand(0, 0xffff),
mt_rand(0, 0xffff),
mt_rand(0, 0x0fff) | 0x4000,
mt_rand(0, 0x3fff) | 0x8000,
mt_rand(0, 0xffff), mt_rand(0, 0xffff), mt_rand(0, 0xffff)
);
} Generate UUID v4 using PHP mt_rand function |
| Go | import "github.com/google/uuid"
id := uuid.New().String() Generate UUID using Google's uuid package |
| Ruby | require 'securerandom'
id = SecureRandom.uuid Generate UUID using Ruby's SecureRandom |
| Swift | import Foundation
let id = UUID().uuidString Generate UUID using Foundation's UUID class |