UUID Generator — Generate UUIDs v4, v1, v5 Free in Your Browser

UUIDs (Universally Unique Identifiers) are the standard way to generate unique IDs for database records, distributed systems, session tokens, and file names. SimpleTools UUID Generator generates UUIDs in multiple versions, in bulk, right in your browser — with cryptographic randomness.

What Is a UUID?

A UUID is a 128-bit number formatted as a 32-character hexadecimal string with dashes: 550e8400-e29b-41d4-a716-446655440000

The format is xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx where:

• M indicates the UUID version (1, 4, 5, etc.)
• N indicates the UUID variant (8, 9, a, or b for RFC 4122 standard)

UUIDs are designed to be globally unique without central coordination — any two independently generated UUIDs have a negligible probability of collision.

UUID Versions

UUID v4 (Random): The most common type. All 122 bits are cryptographically random. Use this for most purposes — database primary keys, session IDs, file names.

UUID v1 (Time-based): Generated from the current timestamp and MAC address. Sequential in time, which can improve database index performance. Less private since it embeds device information.

UUID v5 (Name-based, SHA-1): Deterministic — the same namespace + name always produces the same UUID. Use when you need a consistent unique ID for a known value (e.g., always the same UUID for a given URL or email).

UUID v7 (Time-ordered, random): A newer standard. Like v4 but with a timestamp prefix, making UUIDs sortable by creation time. Better for database performance than v4.

Features

• Bulk generation: Generate 1 to 1000 UUIDs at once
• Multiple versions: v1, v4, v5, v7
• Format options: Standard dashes, no dashes, uppercase, lowercase, with braces {}
• Copy all: One click to copy all generated UUIDs
• v5 namespace input: Enter a namespace UUID and name for deterministic generation
• No repeats: Each UUID is independently generated — no de-duplication needed

Why Generate UUIDs in the Browser?

If your UUIDs are being generated for any system involving user data, generating them in a cloud API means:

1. The generation request is logged (revealing when and how many IDs were generated)
2. There’s unnecessary network latency
3. There’s no need — the browser can generate cryptographically secure random UUIDs natively

SimpleTools UUID Generator:

✅ Pure browser generation — no API calls
✅ Works offline
✅ Cryptographically secure randomness
✅ Free for any quantity

How It Works

UUID v4 generation uses the Web Crypto API’s crypto.getRandomValues() for cryptographic randomness:

function generateUUIDv4() {
  const bytes = new Uint8Array(16);
  crypto.getRandomValues(bytes);
  
  // Set version bits (v4: 0100)
  bytes[6] = (bytes[6] & 0x0f) | 0x40;
  // Set variant bits (RFC 4122: 10xx)
  bytes[8] = (bytes[8] & 0x3f) | 0x80;
  
  return [...bytes].map((b, i) => 
    [4, 6, 8, 10].includes(i) ? '-' + b.toString(16).padStart(2, '0') 
    : b.toString(16).padStart(2, '0')
  ).join('');
}

This produces UUIDs that are statistically indistinguishable from those generated by production UUID libraries like uuid (npm), java.util.UUID, or Python’s uuid4().

How to Use the UUID Generator

1. Visit simpletools.one/uuid-generator
2. Select the UUID version (v4 for most use cases)
3. Enter the quantity (1 to 1000)
4. Choose formatting options (uppercase, no dashes, etc.)
5. Click Generate
6. Copy individual UUIDs by clicking them, or click Copy All

When to Use Each Version

UUID vs. Other ID Formats

Generate UUIDs at simpletools.one/uuid-generator — cryptographically secure, offline-capable, and completely free.