SAP HCI is designed as Integration System-as-a-Provider (PAAS) which really helps to integrate 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 example: Cleaning soap Adapter, IDoc, HTTP, Mail, SFTP,Ariba, oData. https://s4-hana-cloud-edition03320.techionblog.com/28310801/hana-cloud-integration