SAP CPI stands for SAP Cloud Platform Integration. It is SAP's integration platform as a service (iPaaS), designed to connect cloud and on-premise applications, whether they are SAP or non-SAP. Today it is delivered as the Cloud Integration capability inside SAP Integration Suite, which runs on SAP Business Technology Platform (SAP BTP). Many people in the industry still use the name CPI, so you will see both terms in job adverts and training courses.