Swiftpass builds the aggregated payment system that integrates various payment methods(e.g. Alipay, WeChat Pay) into a single interface. This payment system is primarily divided into two parts. The public cloud service handles online transactions. The private cloud services are deployed within institutions with clearing qualifications, responsible for reconciliation, clearing, and settlement. The whole system is based on spring + java. I was responsible for the clearing and settlement modules of the private cloud service.