Alipay Cross-Border E-Payment Service is a payment solution that allows buyers to pay for goods sold on international partner merchant websites using Renminbi (RMB). Alipay will then remit the sum in a foreign currency to the international merchant in settlement. They have more than 550 million users and facilitate around 8.5 million transactions every day. They provide an API with example code snippets in four languages: ASP, PHP, JAVA and .NET.
In Hong Kong, the most cost-efficient Payment Gateway is GoCoin with a transaction rate of 1% and no additional costs in setup fee or yearly maintenance. However, you may miss out on some of the security features like two factorPayment Gateways (Hong Kong)