Authorize.net is described as 'Payment gateway enabling credit card, ACH, and eCheck processing with APIs, fraud prevention, recurring billing, virtual terminal, and invoicing features' and is a payment processing service in the business & commerce category. There are more than 50 alternatives to Authorize.net, not only websites but also apps for a variety of platforms, including Android, iPhone, SaaS and iPad apps. The best Authorize.net alternative is PayPal. It's not free, so if you're looking for a free alternative, you could try PayPal or GNU Taler. Other great sites and apps similar to Authorize.net are DASH, Skrill, Airwallex and Lemon Squeezy.