UUID/GUID Generator Online - v1, v4, v7

What is UUID/GUID?

UUID (Universally Unique Identifier) or GUID (Globally Unique Identifier) is a 128-bit identifier used to uniquely identify resources in computer systems. The probability of generating two identical UUIDs is extremely low, making them ideal for globally unique identifiers.

UUID Versions

Common Use Cases

Supported Formats

UUID Structure

A standard UUID has 36 characters (32 hexadecimal + 4 hyphens) divided into 5 groups:

The digit M indicates the version (1, 4, or 7). The digit N indicates the variant (always 8, 9, A, or B).

Implementation in Different Languages

// Usando o pacote 'uuid'
import { v4 as uuidv4, v1 as uuidv1 } from 'uuid';

const id = uuidv4(); // UUID v4
console.log(id); // f47ac10b-58cc-4372-a567-0e02b2c3d479

const idV1 = uuidv1(); // UUID v1
console.log(idV1); // 6ba7b810-9dad-11d1-80b4-00c04fd430c8

// Nativo no navegador (crypto API)
const uuid = crypto.randomUUID();
console.log(uuid); // Generates UUID v4

import uuid

# UUID v4 (random)
id = uuid.uuid4()
print(id)  # f47ac10b-58cc-4372-a567-0e02b2c3d479

# UUID v1 (timestamp)
id_v1 = uuid.uuid1()
print(id_v1)  # 6ba7b810-9dad-11d1-80b4-00c04fd430c8

# Como string
id_str = str(uuid.uuid4())
print(id_str)

import java.util.UUID;

// UUID v4 (random)
UUID uuid = UUID.randomUUID();
System.out.println(uuid.toString());

// UUID a partir de string
UUID parsed = UUID.fromString("f47ac10b-58cc-4372-a567-0e02b2c3d479");
System.out.println(parsed);

using System;

// UUID v4 (random)
Guid id = Guid.NewGuid();
Console.WriteLine(id.ToString());

// Different formats
Console.WriteLine(id.ToString("N")); // without hyphens
Console.WriteLine(id.ToString("D")); // with hyphens (default)
Console.WriteLine(id.ToString("B")); // with braces {}

<?php
// Using native function (PHP 8.3+)
$uuid = uuid_create(UUID_TYPE_RANDOM);
echo $uuid;

// Or using ramsey/uuid
use Ramsey\Uuid\Uuid;

$uuid = Uuid::uuid4();
echo $uuid->toString(); // f47ac10b-58cc-4372-a567-0e02b2c3d479
?>

package main

import (
    "fmt"
    "github.com/google/uuid"
)

func main() {
    // UUID v4
    id := uuid.New()
    fmt.Println(id.String())
    
    // UUID v1
    idV1, _ := uuid.NewUUID()
    fmt.Println(idV1.String())
}

-- Enable extension
CREATE EXTENSION IF NOT EXISTS "uuid-ossp";

-- Generate UUID v4
SELECT uuid_generate_v4();

-- Generate UUID v1
SELECT uuid_generate_v1();

-- Use as primary key
CREATE TABLE users (
    id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
    name VARCHAR(100)
);

require 'securerandom'

# UUID v4 (random)
uuid = SecureRandom.uuid
puts uuid # f47ac10b-58cc-4372-a567-0e02b2c3d479

# Without hyphens
uuid_no_dash = SecureRandom.uuid.gsub('-', '')
puts uuid_no_dash

UUID vs Auto-Increment IDs

Best Practices

• Use UUID v4 by default: It is the safest and recommended version for general use
• UUID v7 for databases: If index performance is critical, consider UUID v7
• Avoid UUID v1 in public APIs: May reveal timestamp and network information
• Store as binary: In databases, store UUIDs as BINARY(16) for space savings
• Index correctly: Use appropriate indexes for UUIDs, especially with large volumes
• Don't order by UUID v4: UUID v4s are random, using ORDER BY on them doesn't make sense
• Generate on client when possible: UUIDs can be generated on the frontend/client safely
• Validate format: Always validate received UUIDs to ensure correct format

Security and Privacy

Frequently Asked Questions

Are UUID and GUID the same thing?

Yes, they are essentially the same thing. UUID is the RFC 4122 standard term, while GUID is the term used by Microsoft. Both are 128-bit identifiers with the same format.

What is the probability of collision?

For UUID v4, the probability is extremely low: approximately 1 in 2^122 (5.3 × 10^36). In practice, the chance of collision is negligible, even in large-scale systems.

Is UUID case-sensitive?

No. UUIDs are hexadecimal and are not case-sensitive. "f47ac10b..." and "F47AC10B..." represent the same UUID. However, the convention is to use lowercase.

Can I use UUID as a URL?

Yes! UUIDs are safe for URLs. They don't contain special characters that need encoding. Example: https://api.example.com/users/f47ac10b-58cc-4372-a567-0e02b2c3d479

Is UUID slower than auto-increment?

In terms of database insertion, yes, UUIDs can be slightly slower due to size (128 bits vs 32-64 bits) and random nature (index fragmentation). However, UUID v7 solves much of this problem with sortable IDs.

Can I generate UUID offline?

Yes! UUIDs can be generated completely offline without internet or server connection. UUID v4 uses only local random numbers, ensuring global uniqueness without coordination.

How do I validate a UUID?

Use regex: /^[0-9a-f]8-[0-9a-f]4-[1-7][0-9a-f]3-[89ab][0-9a-f]3-[0-9a-f]12$/i
Or use native libraries that have built-in validation.