In a nut-shell, SAP Fiori is a new browser-based user interface to be used in lieu of (or in tandem) with the use SAP GUI interface. The SAP GUI requires end users to install a fat client (aka a thick) client onto the end users computer in order to use and process transactionis. With SAP Fiori, the standard web browsers (supporting HTML5) such as Chrome, Edge, and Firefox can be used to access the Fiori apps to process business transactions in SAP. Allowing the user to access required apps through the browsers reduces overhead from IT to setup and updated the SAP GUI or thick clients on the end users’ computer or device. Another advantage of a responsive HTML5 support is the ability to access Fiori apps through mobile devices and tablets.
SAP Fiori was announced in 2013 and released in 2014. A common misconception is that you need to be on S/4HANA. However, it can be used against a traditional ECC environment, through native Fiori app capability is limited. Fiori is supported on iOS, Android, and Windows with the number of native apps growing with each release.