Free UUID v4 Generator that works offline
Generate one or many version 4 UUIDs for test data, database rows and distributed systems. Random bytes come from the browser’s cryptographic random number generator and the correct version and variant bits are applied.
What this uuid v4 generator does
A UUID is a 128-bit identifier commonly displayed as 32 hexadecimal digits separated by hyphens. Version 4 reserves several bits for format information and fills the remaining bits randomly. The enormous value space makes accidental collisions exceptionally unlikely when UUIDs are generated correctly.
How to use the UUID v4 Generator
- Choose a quantity from one to one hundred.
- Optionally select uppercase output or remove hyphens.
- Generate a fresh batch of version 4 identifiers.
- Copy all results as a newline-separated list.
Common uses
- Creating primary keys before records reach a database
- Generating mock API payloads and fixtures
- Naming temporary resources across distributed clients
- Replacing sensitive production identifiers in examples
Private processing and offline access
This tool does not submit your input to a conversion server. Processing takes place inside the browser using local JavaScript and standard Web APIs. After the PWA has been installed or cached, the page and its core features remain available without an internet connection. Closing or clearing the page removes unsaved input; the tool does not create an account or cloud history.
Tips for accurate results
- Store UUIDs in a native UUID database type when one is available.
- Removing dashes changes presentation, not the underlying 128-bit value.
- UUIDs are identifiers, not authentication secrets or proof of authorization.
Frequently asked questions
Are these real version 4 UUIDs?
Yes. They use cryptographic random bytes and set the RFC version and variant bit pattern.
Can two generated UUIDs collide?
A collision is theoretically possible but extraordinarily unlikely with a reliable random source.
Is a UUID safe to use as a password?
No. UUIDs are designed as identifiers, not as passwords or access-control tokens.