BTCPay Server is described as 'Open Source payment processor conforms to the invoice API of Bitpay. Thllows easy migration of your code base to your own, self-hosted payment processor' and is an app in the Bitcoin & Cryptocurrency category. There are more than 10 alternatives to BTCPay Server for a variety of platforms, including Online / Web-based, Self-Hosted solutions, PHP, Wordpress and Android. The best alternative is CoinPayments. It's not free, so if you're looking for a free alternative, you could try Bubble by V0LT or Bitcoin Payment Gateway for WooCommerce. Other great apps like BTCPay Server are OpenNode - Bitcoin Payment Processor (Paid), BitPay (Paid), BitcartCC (Free, Open Source) and NOWPayments (Free).
If you want to sell digital content online, there's plenty of options out there. However, if you want to sell digital content online without violating your users' privacy in the process, you'll have a much harder time finding a suitable program.
Bitcoin Payment Gateway. Bitcoin Payment Processor - Accept Bitcoin, Bitcoin Cash, Litecoin, Dogecoin, Dash, etc Payments on your website today for user premium membership, file downloads or selling your products! It is Easy! White Label Bitcoin Payment Boxes with your own logo!