SAP HCI is made as Integration System-as-a-Services (PAAS) which helps you to combine various independent techniques/apps for a company system. HCI can perform Cloud to Cloud, Cloud to On-premise, On-premise to On-premise and Hybrid product. HCI offers Adapters (Connectivity alternatives) for instance: Cleaning soap Adapter, IDoc, HTTP, Mail, SFTP,Ariba, oData. https://s4-hana-cloud-sap-notes46802.ageeksblog.com/27627911/hana-cloud-integration