Balou Tools

UUID & NanoID Generator

Generate cryptographically secure identifiers (UUID v4, UUID v7, or NanoID) directly in your browser. No data is sent to any server.

UUID / NanoID Generator Settings

Generated IDs (0)

The generated IDs will be output here.

Collision & sortability

Entropy 122 bit
Batch collision risk < 1e-12
Sortable No
Collision risk

For this batch size the mathematical collision risk is extremely small.

Guide & best practices

UUID Generator for v1, v4 and v7

Generate unique identifiers in several UUID versions – locally in the browser, single or in batch.

Typical use cases

Useful for database IDs, correlation/trace IDs, test data and distributed systems without central ID assignment.

How Balou generates UUIDs

Choose version and count plus format options; Balou generates the UUIDs locally in the browser.

UUID best practices

Use v4 for random IDs, v7 when time sortability is desired and avoid v1 if MAC/time should not be exposed.

Frequently asked questions

v4 vs v7 – when to use which?

v4 is purely random, v7 includes a timestamp and is therefore sortable – ideal as a database key with good index locality.

Are UUIDs guaranteed unique?

Not mathematically guaranteed, but the collision probability for v4/v7 is practically negligible.

What distinguishes v1 from v4?

v1 is based on time and (often) MAC address, v4 on randomness; v4 exposes no hardware/time information.

Are the UUIDs generated server-side?

No, generation runs locally in the browser.