A UUID generator online makes it effortless to create universally unique identifiers (UUIDs) for databases, APIs, file naming, and more - all without installing anything or writing a single line of code. UUID v4 is the most widely used variant and is generated using random numbers, making collisions practically impossible.
What is a UUID?
A UUID (Universally Unique Identifier), also called a GUID (Globally Unique Identifier), is a 128-bit label used in computing to uniquely identify information. A typical UUID v4 looks like this: 550e8400-e29b-41d4-a716-446655440000. Because the identifier is generated randomly, you can create millions of UUIDs across distributed systems without any central coordination and be statistically certain they will never collide.
UUID v4 is defined in RFC 4122 and is by far the most common type because it requires no namespace, clock, or node information - just a secure random number generator, which every modern browser provides natively.
How to Use the UUID Generator
- Set the quantity - enter how many UUIDs you need. You can generate a single ID or hundreds at once.
- Click Generate - the tool produces the requested UUIDs using the browser's built-in cryptographic API (
crypto.randomUUID()). - Copy the output - click the copy button to grab all UUIDs at once, or select individual ones as needed.
Common Use Cases
- Primary keys for PostgreSQL, MySQL, MongoDB, or SQLite tables
- Generating correlation IDs for distributed service tracing
- Creating unique filenames for uploaded assets in cloud storage
- Seeding test databases with realistic-looking unique IDs
- Assigning idempotency keys to API requests
- Building demo data sets for frontend or backend development
Frequently Asked Questions
What is the difference between UUID v4 and UUID v1? UUID v1 is generated from the current timestamp and the machine's MAC address, which can expose hardware information. UUID v4 is generated entirely from random bytes, offering better privacy and no dependency on time or hardware.
Is a UUID truly unique? In practice, yes. The probability of generating two identical UUIDs v4 is astronomically low - roughly 1 in 5.3 × 10³⁶. For any real-world application, you can treat them as unique.
Can I use these UUIDs in production code?
Absolutely. The generator uses the browser's crypto.randomUUID() function, which is cryptographically secure and suitable for production identifiers.
What is the format of a UUID?
A UUID is written as 32 hexadecimal digits separated by hyphens in the pattern 8-4-4-4-12, for example: a4e5c8d1-3b2f-4a6e-9d7c-1f2e3a4b5c6d.
Use the UUID Generator free, no sign-up required.