UUID generator
Generate UUID v4 identifiers, one at a time or in a batch, from your browser cryptographic generator. A v4 UUID is 128 bits, of which 122 are random, so two generated at the same instant on two machines will not collide. The identifiers are minted on your device with nothing transmitted.
- 100% local
- Free · no account
- Instant result
This tool runs entirely in your browser — nothing is sent to a server.
A UUID (Universally Unique Identifier) is a 128-bit identifier designed to be unique without central coordination: two systems can generate them simultaneously with no realistic risk of collision. Version 4, the most common, is entirely random (122 bits of randomness).
This generator produces v4 UUIDs via crypto.randomUUID, the browser’s cryptographic API — one at a time or in batches of several hundred, copyable with one click for your databases, tests and scripts.
How it works
Type the figures or drop the file you want to process — the tool checks them as you go.
Everything is computed directly in your browser. Nothing is sent to a server.
The result appears instantly, with the detailed breakdown ready to copy, download or keep.
Why use this tool
No account, no download, no limit: the result appears as soon as you enter your data.
Every rule, algorithm and check reflects what we use ourselves every day at Flexina.
The calculations follow the official standards, and the step-by-step detail lets you double-check the outcome.
What does running it locally bring you?
Files, figures and documents never leave your device: nothing is stored, nothing is sent.
Once the page is loaded, you can cut the network: the tool keeps working.
No upload, no account, no third-party server in between: results stay fast and fully private.
Frequently asked questions
Can two UUIDs be identical?
In theory yes, in practice no: with 122 bits of randomness, you would need to generate billions of UUIDs per second for decades to have a non-negligible probability of collision.
UUID v4 or v7, which to choose?
v4 is random and universally supported. v7, more recent, starts with a timestamp, making it sortable and friendlier to database indexes. For a plain identifier, v4 is perfectly fine.
Is a UUID a secret?
No: it is unpredictable but often exposed (URLs, APIs). Do not use it as an authentication token on its own.