Generate UUIDs Online
This free UUID generator creates random version 4 UUIDs instantly — one at a time or hundreds at once. Set how many you need and press Generate, then copy the list. The UUIDs are generated in your browser using a cryptographically secure random source, so they are suitable for real use, not just placeholders.
How to Use the UUID Generator
- Enter how many UUIDs you want.
- Press Generate.
- Copy the list of v4 UUIDs.
What a UUID Is
A UUID (Universally Unique Identifier), also called a GUID, is a 128-bit identifier written as 32 hexadecimal digits in five groups separated by hyphens, like 550e8400-e29b-41d4-a716-446655440000. Its purpose is to be unique without any central authority assigning it — you can generate one anywhere, anytime, and be confident it will not collide with another. Version 4 UUIDs are made from random numbers, which is the most common type for general use.
Where UUIDs Are Used
UUIDs are everywhere in software. Databases use them as primary keys so records can be created on different servers without coordinating IDs. APIs use them as request and resource identifiers. Distributed systems, message queues, file names, and session tokens all rely on UUIDs to avoid clashes. Because a v4 UUID has 122 random bits, the chance of two ever colliding is astronomically small, which is why developers trust them as globally unique handles.
Why Version 4?
There are several UUID versions, but version 4 — random — is the most widely used because it needs no input data, no MAC address, and no timestamp. It is simple, privacy-friendly (it leaks no information about where or when it was made), and effectively collision-proof for practical purposes. This generator produces standards-compliant v4 UUIDs with the correct version and variant bits set, so they will validate anywhere a v4 UUID is expected.
Secure and Instant
The UUIDs are generated locally using your browser’s cryptographic random number generator, so they never touch a server and are safe to use as real identifiers. Generation is instant even for hundreds at once, with no signup or limit. If you just need test data or production keys, copy them straight from the output box.
Frequently Asked Questions
What is a v4 UUID?
A 128-bit identifier built from random numbers, written as 32 hex digits in five hyphen-separated groups. It is globally unique without any central authority.
Are these UUIDs safe to use in production?
Yes — they are generated with a cryptographically secure random source and are standards-compliant v4 UUIDs.
Is the UUID generator free and private?
Yes — it is free, needs no signup, and generates everything in your browser.
UUIDs vs. Auto-Increment IDs
A frequent design decision is whether to identify database records with sequential auto-increment numbers or with UUIDs, and generating test UUIDs helps developers explore the trade-offs. Auto-increment IDs are compact and ordered, but they reveal how many records exist, can be guessed, and clash when you try to merge data from multiple databases. UUIDs solve those problems: because they are effectively unique everywhere, records can be created independently on many servers, in offline clients, or across distributed systems and later combined without collisions. They also do not leak record counts or invite easy enumeration.
The cost is size and ordering — a UUID is larger than an integer and is random rather than sequential, which can affect database index performance. For many modern applications, especially distributed ones and public APIs, those downsides are well worth the uniqueness and unguessability. Whether you need a batch of UUIDs as primary keys, request IDs for tracing, idempotency keys for safe API retries, or just unique file names, this generator produces standards-compliant version 4 UUIDs instantly, generated securely in your browser so they are ready for real use.