UUID Generator

About This Tool

A UUID (Universally Unique Identifier) is a 128-bit identifier standardized by the Open Software Foundation (OSF) as part of the Distributed Computing Environment (DCE). UUIDs are designed to be unique across both space and time, making them ideal for use as identifiers in distributed systems without requiring a central coordination authority. This tool generates UUID v4 (random) and UUID v7 (time-ordered) identifiers, supporting single generation, bulk generation of up to 1,000 UUIDs, and auto-copy for streamlined workflows.

UUID v4 generates identifiers using random numbers, which means each of the 122 random bits provides approximately 5.3 × 10^36 possible values — essentially guaranteeing uniqueness. UUID v7 is a newer format that encodes a Unix timestamp in the most significant bits, making the identifiers sortable and more efficient for database indexing (particularly in B-tree indexes used by most relational databases). While v4 is more commonly supported across systems, v7 offers performance advantages for database primary keys and time-series data.

Common Use Cases

• Generating unique primary keys for database tables (especially distributed databases)
• Creating session IDs and correlation IDs for API request tracing and debugging
• Generating unique identifiers for distributed systems where centralized ID generation is impractical
• Creating unique file names to prevent collisions in storage systems and CDNs
• Generating transaction IDs for e-commerce, banking, and payment systems
• Creating unique entity IDs for microservices communication and event sourcing

Pro Tips

• UUID v7 is time-ordered, making it significantly better for database indexing performance than v4
• Use bulk mode to generate multiple UUIDs at once for seeding test data or populating columns
• Enable auto-copy to have each generated UUID automatically copied to your clipboard
• Use uppercase UUIDs for systems or protocols that expect uppercase formatting

Frequently Asked Questions

What is the difference between UUID v4 and v7?

UUID v4 is randomly generated — every bit is random, producing unique but unsorted identifiers. UUID v7 encodes a timestamp in the first bits, making identifiers time-sortable and more efficient for database B-tree indexes. v7 is better for primary keys, while v4 is better when you want no discernible pattern.

Are UUIDs guaranteed to be unique?

No, UUIDs are not guaranteed to be unique, but the probability of collision is extremely low. For UUID v4, there are approximately 5.3 × 10^36 possible values. You would need to generate billions of UUIDs per second for centuries to have a meaningful chance of collision.

Can I use UUIDs as database primary keys?

Yes, but with considerations. UUID v7 is preferred for database primary keys because its time-ordered nature reduces page splits in B-tree indexes. UUID v4 may cause index fragmentation. UUIDs also use more storage space than auto-incrementing integers (128 bits vs 32-64 bits).

What is the difference between UUID and GUID?

GUID (Globally Unique Identifier) is Microsoft's implementation of the UUID standard. The terms are often used interchangeably, and both follow the same RFC 4122 specification. There is no practical difference for most use cases.

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