developer utility
UUID Generator
Generate UUIDs Online — Fast, Free & Secure
Generate random UUIDs online with our free UUID generator. Create UUID v4, UUID v7 and other supported UUID formats, generate multiple UUIDs at once, copy results instantly, or download them for your projects.
UUID Generator
Client-side generationUUID versions
Available UUID Versions
why use our tool
Features Built for Developers
Privacy First
All UUIDs are generated client-side using Web Crypto API. Your data never leaves your browser.
Fast & Efficient
Generate up to 1000 UUIDs instantly. Bulk generator supports 10,000 UUIDs with no server delay.
Multiple Formats
Support for lowercase, uppercase, hyphenated, and non-hyphenated UUID formats.
Export Options
Download generated UUIDs as TXT or CSV files for easy integration into your projects.
complete guide
Understanding UUIDs: A Comprehensive Guide
A UUID (Universally Unique Identifier) is a 128-bit value used to uniquely identify information in computer systems. Our free UUID generator online tool makes it easy to create these identifiers for your applications, databases, and APIs. Whether you need a random UUID generator for general purposes or a specific UUID v7 generator for time-ordered identifiers, this tool has you covered.
Why Use a UUID Generator?
UUIDs solve a fundamental problem in distributed systems: creating unique identifiers without central coordination. Unlike auto-incrementing integers, UUIDs can be generated independently across multiple servers, making them ideal for distributed systems, microservices, and APIs. Our online UUID generator provides a quick, free way to generate these identifiers for testing, development, or production use.
UUID Versions Explained
There are several UUID versions, each with different generation methods:
UUID v4 - Random UUID Generator
The most common version, UUID v4, uses random or pseudo-random values for 122 of its 128 bits. This random UUID generator approach provides excellent uniqueness with minimal complexity. Use our UUID v4 generator for general-purpose identifiers.
UUID v7 - Time-Ordered UUID Generator
UUID v7 is the modern choice for databases and distributed systems. It includes a Unix timestamp in milliseconds in its first 48 bits, making UUIDs sortable by creation time. This time-ordered UUID approach improves database index performance. Our UUID v7 generator produces these efficiently.
UUID v1 - Timestamp + Node
UUID v1 combines a timestamp with the generating machine's MAC address. While still used, it has privacy implications due to MAC address exposure. Our UUID v1 generator simulates this format without hardware dependency.
UUID vs GUID: What's the Difference?
Many developers ask about the difference between UUID and GUID. In practice, they're the same concept - both are 128-bit identifiers designed for uniqueness. GUID (Globally Unique Identifier) is Microsoft's implementation of UUID, commonly used in Windows and .NET environments. Our GUID generator produces identifiers compatible with Microsoft systems.
Bulk UUID Generation
For projects requiring many identifiers, our bulk UUID generator can create up to 10,000 UUIDs in a single batch. This UUID generator tool supports uppercase, lowercase, hyphenated, and non-hyphenated formats, with options to download as TXT, CSV, or JSON files. This feature is particularly useful for database seeding, test data generation, or batch API operations.
UUID Collision Probability
A common question is "Are UUIDs truly unique?" The answer is nuanced. For UUID v4, with 122 random bits, the probability of collision is approximately 1 in 2^122. To put this in perspective, you'd need to generate about 2.71 × 10^18 UUIDs to have a 50% chance of a single collision. While mathematically possible, collisions are practically negligible for most applications. UUID v7 combines timestamp with random bits, further reducing collision risk in time-ordered scenarios.
Best Practices for Using UUIDs
- Choose the right version: Use UUID v4 for general purposes, UUID v7 for databases and time-ordered scenarios.
- Consider database impact: UUIDs can cause index fragmentation. Use UUID v7 for better index locality.
- Store efficiently: UUIDs can be stored as 16-byte binary fields rather than 36-character strings to save space.
- Validate input: Use our UUID validator to ensure identifiers are properly formatted.
- Avoid exposing UUID v1: If privacy is a concern, avoid UUID v1 as it contains the generating machine's MAC address.
How to Generate UUIDs in Different Languages
While our online tool is convenient for quick generation, developers often need to generate UUIDs programmatically. Here are examples in popular languages:
frequently asked questions
Everything you need to know about UUIDs
What is a UUID? +
A Universally Unique Identifier (UUID) is a 128-bit identifier standardized by RFC 9562. It's used to identify information in computer systems without requiring central coordination. UUIDs are commonly used in databases, APIs, distributed systems, and microservices to ensure unique identification across different systems and time periods.
What is a UUID v4? +
UUID version 4 is a randomly generated UUID that uses random or pseudo-random values for 122 of its 128 bits. It's the most commonly used UUID version for general purposes due to its simplicity and extremely low collision probability. The remaining bits indicate the version (4) and variant (RFC 9562).
What is a UUID v7? +
UUID version 7 is a time-ordered UUID that includes a Unix timestamp in milliseconds in its first 48 bits. This makes UUIDs sortable by creation time, which significantly improves database index locality. UUID v7 is recommended for modern applications that require both uniqueness and chronological ordering.
Are UUIDs unique? +
UUIDs are designed to make collisions extremely unlikely but not mathematically impossible. For UUID v4, the probability of collision is approximately 1 in 2^122 (about 1 in 5.3 × 10^36). While theoretically possible, collisions are practically negligible for most applications. UUID v7 further reduces this risk by incorporating timestamps.
Can I generate multiple UUIDs? +
Yes, you can generate 1, 5, 10, 25, 50, 100, 500, or 1000 UUIDs at once using our main generator. For larger batches, our bulk UUID generator supports up to 10,000 UUIDs in a single operation with options to download as TXT, CSV, or JSON files.
Is this UUID generator free? +
Yes, this UUID generator is completely free to use. There's no registration required, no usage limits, and no hidden fees. We believe essential developer tools should be accessible to everyone without barriers.
Are generated UUIDs stored? +
No, all UUIDs are generated directly in your browser using the Web Crypto API. Your UUIDs never leave your device and are not transmitted to our server. This ensures complete privacy and security for your generated identifiers.
What is the difference between UUID and GUID? +
UUID (Universally Unique Identifier) and GUID (Globally Unique Identifier) are essentially the same concept. GUID is Microsoft's implementation of UUID, commonly used in Windows, .NET, and SQL Server environments. While technically compatible, GUIDs often follow Microsoft's specific format conventions and may use different byte ordering in some contexts.