A UUID (Universally Unique Identifier), also called a GUID, is a randomly generated 128-bit identifier designed to have an essentially zero chance of colliding with another one, even when generated on different machines or systems at the same time. Developers use UUIDs widely as database primary keys, session identifiers, transaction identifiers, or object IDs in distributed systems that need unique identifiers without relying on a central server to check for duplicates. This tool generates version 4 (v4) UUIDs, the most commonly used version, since they're derived purely from random numbers with no embedded timestamp or machine address like other UUID versions. Generate several at once, choose uppercase or lowercase, and include or omit hyphens to match whatever format your system expects. Everything runs entirely in your browser — nothing is ever sent to a server.
How to use the UUID generator
Choose a count and format
Adjust how many you need, uppercase/lowercase, and hyphens
Generate new UUIDs
Click generate to create an unlimited number of new batches
Copy and use them
Copy one at a time, or copy the whole batch at once
Why use this tool
Cryptographically secure
Uses crypto.getRandomValues, not an ordinary Math.random
Generate in bulk
Up to 50 at once, handy for test data
Format your way
Choose uppercase/lowercase and with or without hyphens
Example use cases
Database primary keys
Use UUIDs instead of auto-increment IDs so records can be created from multiple machines or services simultaneously without colliding.
Session or token identifiers
Generate unpredictable, unique session IDs or temporary API keys that won't collide with other users'.
Object IDs in distributed systems
Identify files, orders, or events in a microservices system where each part can generate its own ID without asking a central authority.
Mock/test data
Generate a batch of fake IDs for testing a system or seeding a database during development.