UUID Generator - Create Random v1, v4, v5 UUIDs Online Free

What is UUID Generator?

UUID Generator creates unique identifiers that work across any system without a central database. A UUID (Universally Unique Identifier) is a 128-bit number formatted as 32 hex digits with dashes, like "550e8400-e29b-41d4-a716-446655440000". This tool generates UUIDs in three popular versions and can also validate existing UUIDs.

Why Would You Need to Generate UUIDs?

Here are common situations where UUIDs come in handy:

• Database primary keys: Use UUIDs instead of auto-increment IDs when merging databases or working with distributed systems.
• API identifiers: Create unique IDs for API resources that don't reveal record counts or creation order.
• Session tokens: Generate unpredictable session identifiers for user authentication.
• File naming: Create unique filenames for uploads without worrying about collisions.
• Tracking and analytics: Assign unique IDs to users, events, or transactions for tracking purposes.

How to Generate UUIDs - Step by Step

1. Choose your UUID version: Click on v1 (time-based), v4 (random), or v5 (name-based) depending on your needs. v4 is selected by default and works for most cases.
2. Set the quantity: Select how many UUIDs you need - from 1 to 100 at a time.
3. For v5 only: Select a namespace (DNS, URL, etc.) and enter a name to hash.
4. Click Generate: Your UUIDs appear instantly in a list.
5. Copy what you need: Click the copy button next to any UUID, or use "Copy All" to grab the entire list.

How to Validate a UUID - Step by Step

1. Switch to Validate tab: Click "Validate & Parse" at the top.
2. Paste your UUID: Enter the UUID you want to check. The tool accepts standard format, with braces, or URN format.
3. Click Validate: See if it's valid, what version it is, and get alternative formats.

Key Features

• Three UUID versions: Generate v1 (time-based), v4 (random), or v5 (name-based) UUIDs
• Bulk generation: Create up to 100 UUIDs at once
• UUID validation: Check if any UUID is valid and identify its version
• Multiple formats: Get your UUID in lowercase, uppercase, with braces, URN, hex, or Base64
• Predefined namespaces: Use standard namespaces (DNS, URL, OID, X.500) for v5 UUIDs
• Custom namespaces: Enter your own namespace UUID for v5 generation
• One-click copy: Copy individual UUIDs or the entire list

Understanding UUID Versions

• UUID v1 (Time-based): Uses current timestamp and a node ID. Good when you need sortable IDs, but reveals creation time.
• UUID v4 (Random): Completely random. The most common choice - simple, private, and collision-resistant.
• UUID v5 (Name-based): Creates the same UUID for the same namespace + name combination. Useful for creating predictable IDs from known inputs.

Tips for Best Results

• Use v4 (random) for most applications - it's the simplest and most secure choice
• Use v1 when you need to sort records by creation time based on the UUID
• Use v5 when you need the same input to always produce the same UUID
• Store UUIDs as binary (16 bytes) in databases for better performance

Frequently Asked Questions

Will two UUIDs ever be the same?

Technically possible, but incredibly unlikely. With v4, you'd need to generate about 1 billion UUIDs per second for 85 years to have a 50% chance of one collision. For practical purposes, treat them as always unique.

Which UUID version should I use?

Use v4 (random) for most cases. Use v1 if you need time-sortable IDs. Use v5 if you need deterministic IDs based on a name.

Are UUIDs secure?

v4 UUIDs are cryptographically random and safe for security-sensitive uses. v1 UUIDs reveal creation time and should be avoided if timing information is sensitive.

How do I store UUIDs in a database?

Store as BINARY(16) for best performance, or as CHAR(36) for readability. Many databases have native UUID types (PostgreSQL, for example).