You can signup and get started with a test integration: https://www.adyen.com/signup https://www.adyen.com/signup But to be approved you need to talk with them

You can signup and get started with a test integration: https://www.adyen.com/signup https://www.adyen.com/signup But to be approved you need to talk with them. As long as what you're doing is a real company (and you have documentation to prove it), they'll approve you. But you do need to setup a proper business before being able to go live with payments.