SAP HCI is made as Integration System-as-a-Company (PAAS) which really helps to combine many unbiased devices/apps for a business method. HCI can do Cloud to Cloud, Cloud to On-premise, On-premise to On-premise and Hybrid model. HCI features Adapters (Connectivity options) such as: Cleaning soap Adapter, IDoc, HTTP, Mail, SFTP,Ariba, oData. https://s4-hana-cloud-architectur47923.jts-blog.com/27730788/hana-cloud-integration