In order to use FullPage legally, you need to have a license key.

Once you purchase a fullPage license you will receive an email from Gumroad with a license key. (If it's not on your inbox check the SPAM folder.)

You might be wondering where and how to use this license number in your source code.

Well, it is pretty easy. As detailed on the fullPage documentation, you'll just have to add the option licenseKey when initializing fullpage.js:

licenseKey: (default null). This option is compulsory.

• Be aware of the spelling: the letter "K" is in uppercase! (licenseKey)

• If you do not add this option (or you spell it wrong) the console javascript will warn you with this error: Fullpage.js version 3 has changed its license to GPLv3 and it requires a licenseKey option.

Here is the relevant code that you have to add to your source code:

new fullpage('#fullpage', {
    licenseKey: 'YOUR_KEY_HERE'
})

If you are wondering how you can hide the licenseKey on your fullPage.js initialisation, the short answer is: you can't. 

And if you are a bit confused about what license to need, check this article regarding which fullPage.js license you should get.

You might also find these articles relevant:

• Can I change the activated domain of my extension?
• Can I use fullpage.js on my client's website?
• How to fix 'Unlicensed extension' red error message
• How can I upgrade my fullPage.js extension?
• Can I use my fullPage.js license on multiple projects?