# UUID

**The UUID function returns a new UUID `string` each time it is called.**

This function requires no input. It returns a `string` containing a new UUID, or "Universally Unique Identifier," each time it is called.

#### Declaration

```javascript
UUID() -> uuid_string
```

#### Parameters

The UUID function recognizes no input parameters.

#### Return Values

**uuid\_string**(type: `string`) A new UUID. This value is not tied to any user [Journey](../../concepts/journeys), and the returned UUID will be different each time the UUID function is called.

#### Examples

The following example uses the UUID function to generate a new Universally Unique Identifier:

```javascript
UUID() => "5ac1ad79-30a7-4597-aec6-04fb96c8425e"
```

Each time the UUID function is called, it returns a different value. Should it be called again, such as in the following example, it will return a different Universally Unique Identifier:

```javascript
UUID() => "763bc718-cd30-4af4-b139-4e201978f57c"
```

#### Discussion

The UUID function returns a Universally Unique Identifier (UUID), or, as it sometimes referred to as, a Globally Unique Identifier (GUID). Both names refer to 128-bit labels that are functionally unique. This is not because the generated identifiers are registered anywhere, but because they contain enough degrees of freedom that any chance of duplication is close enough to zero to be negligible. For more on UUIDs, see [the Wikipedia article](https://en.wikipedia.org/wiki/Universally_unique_identifier).

The UUID function can be used to generate functionally unique identifiers independent of any identifiers Airkit assigns automatically. Note that the values returned by UUID functions are not saved anywhere in Airkit unless you explicitly save them as part of your application.
