# License key

To use HyperFormula, you need to specify which [license type](licensing.md#available-licenses) you use, by entering a license key in your [configuration options](configuration-options.md).

## GPLv3 license

If you use HyperFormula under [GNU General Public License v3.0](https://github.com/handsontable/hyperformula/blob/master/LICENSE.txt) (GPLv3), in your [configuration options](configuration-options.md), assign the mandatory `licenseKey` property to a string, `gpl-v3`:

```js
const options = {
  licenseKey: 'gpl-v3',
  //... other options
}
```

## Proprietary license

To use HyperFormula under a [proprietary license](licensing.md#proprietary-license), follow these steps:

1. Contact our [Sales Team](licensing.md#proprietary-license) to purchase a proprietary license.
2. Our Sales Team sends you your proprietary license key.
3. In your [configuration options](configuration-options.md), assign the mandatory `licenseKey` property to your proprietary license key:

```js
const options = {
  // replace xxxx-xxxx-xxxx-xxxx-xxxx with your proprietary license key:
  licenseKey: 'xxxx-xxxx-xxxx-xxxx-xxxx',
  //... other options
}
```

### Proprietary license key validation

> HyperFormula doesn't use an internet connection to validate your proprietary license key.

To determine whether a user is still entitled to use a particular
version of the software, HyperFormula compares the time between
two dates:
* The HyperFormula build date
* The date in your proprietary license key

This process doesn't require any connection to the server.

## License key notifications

If your license key is missing, invalid, or expired, you see a
corresponding notification in the console.

## License key support

If you have any issues with your license key, [contact our team](contact.md).