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UUID Generator

Generate universally unique identifiers (UUIDs) in various formats. Supports UUID v1, v4, and v7 with different formatting options for your development needs.

βš™οΈ Configuration

UUID Version Comparison

UUID v1 (Time-based)

  • β€’ Based on timestamp and MAC address
  • β€’ Chronologically sortable
  • β€’ May reveal system information
  • β€’ Not recommended for security-sensitive uses

Example: 51043126-0197-1-9ee3-fcdcaacc0530

UUID v4 (Random)

  • β€’ Completely random
  • β€’ Most commonly used
  • β€’ No privacy concerns
  • β€’ Recommended for most applications

Example: a19ef855-fdd2-4d7b-a542-e5343c461911

UUID v7 (Modern Time-based)

  • β€’ Timestamp-based but privacy-friendly
  • β€’ Chronologically sortable
  • β€’ Better database performance
  • β€’ Newer specification (2022)

Example: 01975104-3127-7df4-bfd4-b00668cc1d88

Common Use Cases

πŸ—ƒοΈ Database Records

  • β€’ Primary keys for distributed systems
  • β€’ Unique identifiers across microservices
  • β€’ Non-sequential IDs for security
  • β€’ Global uniqueness without coordination

🌐 Web Development

  • β€’ Session IDs and tokens
  • β€’ File upload identifiers
  • β€’ API request tracking
  • β€’ Cache keys and temporary data

πŸ“± Mobile & Desktop Apps

  • β€’ Device identifiers
  • β€’ Local data synchronization
  • β€’ Offline-first applications
  • β€’ Event tracking and analytics

πŸ”§ System Administration

  • β€’ Container and VM identifiers
  • β€’ Log correlation IDs
  • β€’ Configuration management
  • β€’ Asset tracking

Features

🎯

Multiple Versions

Generate UUID v1, v4, and v7 for different use cases.

🎨

Custom Formats

Choose from multiple formatting options and cases.

⚑

Bulk Generation

Generate up to 100 UUIDs at once for bulk operations.

πŸ“‹

Easy Copy

Copy individual UUIDs or all at once for easy use.

Complete UUID Guide: Universally Unique Identifiers Explained

πŸ” Understanding UUIDs

A Universally Unique Identifier (UUID) is a 128-bit number used to identify information in computer systems. UUIDs are designed to be unique across space and time without requiring a central registration authority.

UUID Structure

xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx
M: Version digit (1, 2, 3, 4, 5, 6, 7, 8)
N: Variant bits (8, 9, A, B)
Total: 32 hexadecimal digits
Format: 8-4-4-4-12 character groups

Uniqueness Guarantee

With proper implementation, the probability of generating duplicate UUIDs is negligible. For UUID v4, there are 2^122 possible values (5.3 Γ— 10^36), making collisions extremely unlikely.

πŸ“Š UUID Version Breakdown

VersionBasisSortablePrivacy
v1Timestamp + MACYesLow
v4RandomNoHigh
v7Timestamp + RandomYesHigh

Version Selection Guide

  • β€’ v1: Use when you need chronological sorting but privacy isn't critical
  • β€’ v4: Default choice for most applications, maximum privacy
  • β€’ v7: Best of both worlds - sortable and private (newest standard)

UUIDs in Database Design and Distributed Systems

πŸ—ƒοΈ Primary Keys

UUIDs as primary keys eliminate the need for centralized ID generation in distributed systems.

CREATE TABLE users (
Β Β id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
Β Β email VARCHAR(255) UNIQUE,
Β Β created_at TIMESTAMP DEFAULT NOW()
);

βš–οΈ Database Performance

Challenges:
  • β€’ Random UUIDs cause index fragmentation
  • β€’ Larger storage than integer IDs
  • β€’ Random insertion hurts cache performance
Solutions:
  • β€’ Use UUID v7 for chronological ordering
  • β€’ Consider ULID as alternative
  • β€’ Optimize database for UUID workloads

🌐 Microservices

UUIDs enable independent ID generation across microservices without coordination.

Benefits:
β€’ No single point of failure
β€’ Service independence
β€’ Easy data replication
β€’ Offline capability

πŸ”„ Data Replication

UUIDs eliminate ID conflicts when replicating data across multiple databases or regions.

Use cases:
β€’ Multi-master replication
β€’ Cross-datacenter sync
β€’ Offline-first applications
β€’ Database sharding

πŸ“± Client-side Generation

UUIDs can be generated client-side, reducing server round trips and enabling offline operations.

Advantages:
β€’ Reduced server load
β€’ Better user experience
β€’ Offline functionality
β€’ Optimistic UI updates

πŸ” Security Benefits

UUIDs provide security through obscurity and prevent enumeration attacks on sequential IDs.

Protection against:
β€’ ID enumeration attacks
β€’ Information disclosure
β€’ Predictable resource access
β€’ Business intelligence leakage

Alternative Unique Identifier Systems

πŸš€ Modern Alternatives

ULID (Universally Unique Lexicographically Sortable Identifier)

26-character string that's both unique and lexicographically sortable. Better database performance than UUID v4.

01ARZ3NDEKTSV4RRFFQ69G5FAV

Snowflake ID

Twitter's 64-bit ID scheme: timestamp + machine ID + sequence. Sortable and fits in a long integer.

Format: [41 bits timestamp][10 bits machine][12 bits sequence]

nanoid

URL-safe, compact alternative to UUID. 21 characters, URL-friendly alphabet, faster generation.

V1StGXR8_Z5jdHi6B-myT

πŸ“Š Performance Comparison

TypeSizeSortableDB Perf
UUID v4128-bitNoPoor
UUID v7128-bitYesGood
ULID128-bitYesGood
Snowflake64-bitYesExcellent
nanoidVariableNoFair

Selection Criteria

  • β€’ High-volume databases: Consider Snowflake or UUID v7
  • β€’ URL identifiers: Use nanoid or short UUIDs
  • β€’ Legacy compatibility: Stick with UUID v4
  • β€’ New projects: Consider UUID v7 or ULID

Implementation Best Practices and Common Pitfalls

βœ… Best Practices

πŸ”§ Generation Strategy

  • β€’ Use cryptographically secure random number generators
  • β€’ Generate UUIDs as close to usage as possible
  • β€’ Don't pre-generate large batches of UUIDs
  • β€’ Validate UUID format when receiving from clients

πŸ—„οΈ Database Optimization

  • β€’ Use binary storage format when possible (16 bytes vs 36 characters)
  • β€’ Consider clustered indexes on timestamp-based UUIDs
  • β€’ Use appropriate column types (BINARY(16) or UUID native types)
  • β€’ Monitor index fragmentation with random UUIDs

πŸ”’ Security Considerations

  • β€’ Don't expose UUIDs in URLs if they contain timing information
  • β€’ Use UUID v4 for session tokens and API keys
  • β€’ Avoid UUID v1 in public-facing applications
  • β€’ Consider additional access controls beyond UUID obscurity

⚠️ Common Pitfalls

πŸ’₯ Performance Issues

  • β€’ Using random UUIDs as clustered index keys
  • β€’ Storing UUIDs as strings instead of binary
  • β€’ Not considering index fragmentation
  • β€’ Ignoring cache performance implications

πŸ› Implementation Errors

  • β€’ Using weak random number generators
  • β€’ Incorrect timestamp handling in UUID v1/v7
  • β€’ Not handling UUID format variations
  • β€’ Assuming UUIDs are always lowercase

πŸ—οΈ Design Mistakes

  • β€’ Using UUIDs for everything (including counters)
  • β€’ Not considering client-side generation benefits
  • β€’ Ignoring the need for human-readable identifiers
  • β€’ Over-relying on UUID uniqueness for security

UUID Implementation Examples

🟨 JavaScript

Browser (Crypto API):

// Modern browsers
const uuid = crypto.randomUUID();
console.log(uuid); // e.g., "123e4567-e89b-12d3-a456-426614174000"

// Polyfill for older browsers
function generateUUIDv4() {
  return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, c => {
    const r = Math.random() * 16 | 0;
    const v = c === 'x' ? r : (r & 0x3 | 0x8);
    return v.toString(16);
  });
}

Node.js:

const { randomUUID } = require('crypto');
const uuid = randomUUID();

// Or using uuid package
const { v4: uuidv4, v7: uuidv7 } = require('uuid');
const uuid4 = uuidv4();
const uuid7 = uuidv7();

🐍 Python

Standard Library:

import uuid

# UUID v4 (random)
uuid4 = uuid.uuid4()
print(str(uuid4))  # with hyphens
print(uuid4.hex)   # without hyphens

# UUID v1 (timestamp + MAC)
uuid1 = uuid.uuid1()

# Convert to different formats
uuid_bytes = uuid4.bytes
uuid_int = uuid4.int

β˜• Java

Standard UUID Class:

import java.util.UUID;

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

// Parse from string
UUID parsed = UUID.fromString("123e4567-e89b-12d3-a456-426614174000");

// Get components
long mostSigBits = uuid.getMostSignificantBits();
long leastSigBits = uuid.getLeastSignificantBits();

πŸ—„οΈ SQL Databases

PostgreSQL:

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

-- Generate UUID v4
SELECT uuid_generate_v4();

-- Table with UUID primary key
CREATE TABLE users (
  id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
  email VARCHAR(255) UNIQUE NOT NULL
);

MySQL 8.0+:

-- Generate UUID
SELECT UUID();

-- Binary storage for performance
CREATE TABLE users (
  id BINARY(16) PRIMARY KEY DEFAULT (UUID_TO_BIN(UUID())),
  email VARCHAR(255) UNIQUE NOT NULL
);

Frequently Asked Questions

Q: Are UUIDs truly unique?

A: UUIDs are designed to be unique with extremely high probability. For UUID v4, the chance of collision is negligible (1 in 5.3 Γ— 10^36). However, poor random number generation or implementation bugs can increase collision risk.

Q: Which UUID version should I use?

A: For most applications, use UUID v4 (random). If you need chronological sorting and don't mind revealing timestamp information, consider UUID v7. Avoid UUID v1 unless you specifically need MAC address information and privacy isn't a concern.

Q: Do UUIDs hurt database performance?

A: Random UUIDs (v4) can impact database performance due to random insertion patterns causing index fragmentation. Use binary storage, consider UUID v7 or ULID for better performance, and monitor index maintenance needs.

Q: Can I use UUIDs for security?

A: UUIDs provide security through obscurity but shouldn't be your only security measure. They prevent enumeration attacks but don't replace proper authentication and authorization. Never rely solely on UUID unpredictability for security.

Q: How do I store UUIDs efficiently?

A: Store UUIDs in binary format (16 bytes) rather than as strings (36 characters). Most databases have native UUID types or BINARY(16) columns. This reduces storage space and improves query performance significantly.

Q: Can I generate UUIDs client-side?

A: Yes! Client-side UUID generation is safe and recommended. It reduces server load, enables offline functionality, and improves user experience with optimistic UI updates. Ensure you're using a cryptographically secure random source.

Q: What's the difference between UUID and GUID?

A: UUID and GUID are essentially the same thing. GUID (Globally Unique Identifier) is Microsoft's terminology for the same 128-bit identifier concept. The format and generation methods are identical, just different naming conventions.

Q: Are there alternatives to UUIDs?

A: Yes! Consider ULID for sortable identifiers, Snowflake IDs for high-performance systems, nanoid for URL-friendly IDs, or Cuid for collision-resistant identifiers. Choose based on your specific requirements for sortability, size, and performance.