Developer Utilities
UUID / GUID Generator
Generate high-quality, secure UUID v4, v1, and modern v7 identifiers in bulk. Customize hyphens, casing, braces, and delimiters instantly.
Generation Options
UUID v7 is modern, sequential, and highly index-friendly, making it ideal for high-performance databases.
What is a UUID (Universally Unique Identifier)?
A Universally Unique Identifier (UUID), historically also referred to as a Globally Unique Identifier (GUID) in Microsoft ecosystems, is a 128-bit label used for identifying information in computer systems. Standard UUIDs are structured as 32 hexadecimal characters split across five groups separated by hyphens in a 8-4-4-4-12 configuration (for example, 123e4567-e89b-12d3-a456-426614174000).
Because of the massive range of unique combinations (there are 2128 or roughly 3.4 x 1038 possible UUIDs), the probability of duplicate IDs being generated, even on separate machines without a centralized authority, is virtually zero. This makes them ideal for primary keys in distributed databases, microservice transactions, file identifiers, and secure authentication tokens.
Understanding the Different UUID Versions
Different use cases require different generation strategies. Our bulk generator supports three of the most popular UUID variants:
- Version 4 (Random): Generated entirely from cryptographically secure random bytes (high entropy). This is the most common version used today for file IDs, transaction tokens, and general key parameters.
- Version 7 (Unix Epoch Sortable): The modern standard for databases. It encodes a 48-bit Unix timestamp at the start of the ID, followed by random bits. Since they are chronologically sortable, they maintain B-tree index performance in SQL/NoSQL databases like PostgreSQL and MySQL, preventing the index fragmentation caused by V4.
- Version 1 (Time & Node based): Created using a combination of the system's MAC address and a high-precision Gregorian epoch timestamp. Less common now due to privacy concerns regarding host identification, but still widely used in legacy systems.
Collision Safety & Entropy
To put UUID v4 collision statistics into perspective: if you generated 1 billion UUIDs every single second for the next 100 years, the probability of creating a single duplicate identifier is about 50%. The math is incredibly secure. By using standard browser-level cryptographic methods (window.crypto.getRandomValues), our generator secures absolute randomness directly on your local CPU.
Frequently Asked Questions
Are my generated UUIDs private?
Yes, 100%. All UUID calculations, formatting, and casing are executed directly inside your web browser using client-side JavaScript. No data is transmitted to our servers, ensuring your generated IDs are completely secure, private, and yours alone to use.
Why should I use UUID v7 over UUID v4 for databases?
UUID v4 is completely random, which means inserting new rows creates random insert points. This forces database systems to fragment and restructure B-tree indexes constantly, dragging down performance on large datasets. Because UUID v7 begins with a timestamp, new entries are appended sequentially, preserving high-performance indexing and fast lookups.