UUID Generator - Free Online UUID/GUID Generator Tool
Generate random UUIDs (v4) instantly. Free online UUID/GUID generator with bulk generation. No signup, no data sent to server.
What is UUID Generator?
How to Use UUID Generator
Click "Generate UUID" to create a single random UUID v4. Use the quantity selector to generate multiple UUIDs at once (up to 100). Choose your preferred format: standard (with hyphens), no hyphens, uppercase, or braces (Microsoft GUID style). Click "Copy" to copy all generated UUIDs to your clipboard. Each click generates completely new random UUIDs.
How UUID Generator Works
Common Use Cases
- Generating unique primary keys for database records without auto-increment
- Creating unique identifiers for distributed systems and microservices
- Generating session IDs and authentication tokens for web applications
- Assigning unique correlation IDs for request tracing in API calls
- Creating unique file names for uploaded content to avoid collisions
- Testing and development: generating mock data with realistic unique IDs
Frequently Asked Questions
What is the difference between UUID and GUID?▼
UUID (Universally Unique Identifier) and GUID (Globally Unique Identifier) are essentially the same thing. UUID is the standard term used in RFC 4122, while GUID is the Microsoft-specific term. They follow the same format and generation rules. GUIDs are sometimes displayed with braces: {xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx}.
Are UUID v4 values truly unique?▼
While not mathematically guaranteed to be unique, the probability of a collision is vanishingly small. With 2^122 possible values (approximately 5.3 × 10^36), you could generate 1 billion UUIDs per second for 85 years and still have less than a 50% chance of a single duplicate. For all practical purposes, they are unique.
What UUID version should I use?▼
UUID v4 (random) is the most widely used and recommended for most applications. It is simple, requires no external state, and works well in distributed systems. UUID v7 (time-ordered) is a newer option gaining popularity for database primary keys because it provides both uniqueness and chronological sorting.
Can UUIDs be used as database primary keys?▼
Yes, and this is one of their most common uses. UUIDs avoid the need for centralized auto-increment counters, making them ideal for distributed databases and microservices. However, random UUIDs (v4) can cause index fragmentation in some databases. Consider UUID v7 or ULID for better index performance.
Is this generator secure enough for production use?▼
Yes. This tool uses the Web Crypto API (crypto.randomUUID or crypto.getRandomValues), which provides cryptographically secure random numbers. The generated UUIDs are suitable for production use including session IDs, API keys, and database identifiers.
How many UUIDs can I generate at once?▼
This tool supports generating up to 100 UUIDs at once. Select the desired quantity, choose your preferred format (standard, no hyphens, uppercase, or braces), and click generate. All UUIDs can be copied to clipboard with a single click.