Which type of PayPal account do I need?

Can I use a Personal account or do I need to have a Business account? What type of account should I create with PayPal if I wish to use PayPal payment gateway included in HBook? What PayPal API does HBook use and what are the requirements?

HBook uses PayPal Express Checkout API. We use this API as it is highly secured and reliable. It requires a PayPal Business account.