UUID Generator Guide: Create Unique Identifiers

What is a UUID?

A UUID (Universally Unique Identifier) is a 128-bit identifier that is guaranteed to be unique across time and space. UUIDs are used in software development to create unique identifiers for database records, API endpoints, and distributed systems.

🎯 Why Use UUIDs?

Uniqueness: Guaranteed to be unique across systems
No Central Authority: Can be generated without coordination
Standardized: RFC 4122 standard ensures compatibility
Collision Resistant: Extremely low probability of duplicates
Distributed Systems: Perfect for microservices and APIs
Database Keys: Ideal for primary keys in databases

UUID Versions Explained

Version 1: Time-based

Generated using MAC address and timestamp.

550e8400-e29b-11d4-a716-446655440000

✅ Time-ordered (sortable)
✅ Globally unique
⚠️ Exposes MAC address
⚠️ Predictable sequence

Version 2: DCE Security

Similar to v1 but includes POSIX UID/GID.

6ba7b810-9dad-11d1-80b4-00c04fd430c8

✅ Includes user/group info
✅ Time-ordered
⚠️ Rarely used
⚠️ Limited compatibility

Version 3: Name-based (MD5)

Generated using MD5 hash of namespace and name.

6fa459ea-ee8a-3ca4-894e-db77e160355e

✅ Deterministic
✅ Same input = same UUID
⚠️ MD5 is deprecated
⚠️ Security concerns

Version 4: Random

Generated using random or pseudo-random numbers.

f47ac10b-58cc-4372-a567-0e02b2c3d479

✅ Most secure
✅ No privacy leaks
✅ Widely supported
⚠️ Not sortable

Version 5: Name-based (SHA-1)

Generated using SHA-1 hash of namespace and name.

886313e1-3b8a-5372-9b90-0c9aee199e5d

✅ Deterministic
✅ Better security than v3
✅ Same input = same UUID
⚠️ SHA-1 is deprecated

How to Use Our UUID Generator

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Step 1: Choose UUID Version

Select the appropriate UUID version for your use case.

Pro Tip: Use v4 for most applications, v1 for time-ordered IDs

Step 2: Set Quantity

Choose how many UUIDs you need to generate.

Pro Tip: Generate in batches for better performance

Step 3: Choose Format

Select the output format (standard, uppercase, or without hyphens).

Pro Tip: Use uppercase for better readability

Step 4: Copy and Use

Copy the generated UUIDs and use them in your applications.

Pro Tip: Store UUIDs as strings in databases

UUID Format Breakdown

Standard UUID Format

f47ac10b-58cc-4372-a567-0e02b2c3d479

8 chars

Time Low

4 chars

Time Mid

4 chars

Version

4 chars

Variant

12 chars

Node

🔍 UUID Structure Details

Time Low (32 bits): Low 32 bits of timestamp
Time Mid (16 bits): Middle 16 bits of timestamp
Version (4 bits): UUID version number (1-5)
Variant (4 bits): UUID variant identifier
Node (48 bits): MAC address or random data
Total Length: 128 bits (16 bytes)

Common Use Cases

🗄️ Database Primary Keys

Use UUIDs as primary keys in databases for distributed systems.

CREATE TABLE users (
  id UUID PRIMARY KEY,
  name VARCHAR(255)
);

🌐 API Endpoints

Create unique identifiers for API resources and endpoints.

GET /api/users/f47ac10b-58cc-4372-a567-0e02b2c3d479

🔄 Distributed Systems

Generate unique IDs across multiple services without coordination.

Service A: f47ac10b-58cc-4372-a567-0e02b2c3d479
Service B: 6ba7b810-9dad-11d1-80b4-00c04fd430c8

📁 File Naming

Create unique filenames to avoid conflicts in file systems.

document_f47ac10b-58cc-4372-a567-0e02b2c3d479.pdf

🔐 Session Management

Generate unique session IDs for user authentication.

session_id: f47ac10b-58cc-4372-a567-0e02b2c3d479

📊 Event Tracking

Create unique identifiers for tracking events and analytics.

event_id: f47ac10b-58cc-4372-a567-0e02b2c3d479

Programming Language Examples

🟨 JavaScript/Node.js

const { v4: uuidv4 } = require('uuid');
const id = uuidv4();
console.log(id); // f47ac10b-58cc-4372-a567-0e02b2c3d479

🐍 Python

import uuid
id = uuid.uuid4()
print(id) # f47ac10b-58cc-4372-a567-0e02b2c3d479

☕ Java

import java.util.UUID;
UUID id = UUID.randomUUID();
System.out.println(id); // f47ac10b-58cc-4372-a567-0e02b2c3d479

🦀 Rust

use uuid::Uuid;
let id = Uuid::new_v4();
println!("", id); // f47ac10b-58cc-4372-a567-0e02b2c3d479

🐹 Go

import "github.com/google/uuid"
id := uuid.New()
fmt.Println(id) // f47ac10b-58cc-4372-a567-0e02b2c3d479

🔷 C#

using System;
Guid id = Guid.NewGuid();
Console.WriteLine(id); // f47ac10b-58cc-4372-a567-0e02b2c3d479

Best Practices

✅ Do's

Use Version 4: For most applications, v4 is the best choice
Store as String: Store UUIDs as strings in databases
Validate Format: Always validate UUID format before use
Use Libraries: Use established UUID libraries for generation
Consider Performance: UUIDs are larger than integers
Index Properly: Create proper database indexes for UUIDs

❌ Don'ts

Don't Use v1: Avoid v1 UUIDs in web applications
Don't Generate Manually: Never create UUIDs manually
Don't Use v3/v5: Avoid MD5/SHA-1 based UUIDs
Don't Expose Internally: Don't expose internal UUIDs in URLs
Don't Use as Passwords: UUIDs are not suitable as passwords
Don't Ignore Collisions: Always handle potential collisions

Frequently Asked Questions

What's the difference between UUID and GUID?

UUID and GUID are essentially the same thing. GUID (Globally Unique Identifier) is Microsoft's term for UUID.

Can UUIDs collide?

The probability of UUID collision is extremely low (about 1 in 5.3 x 10^36 for v4 UUIDs), making them practically unique.

Which UUID version should I use?

Use UUID v4 for most applications. Use v1 if you need time-ordered IDs, and v5 if you need deterministic UUIDs.

Are UUIDs secure?

UUID v4 is cryptographically secure when generated with a proper random number generator. Never use UUIDs as passwords or security tokens.

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