HANA XS (also known as SAP HANA Extended Application Services engine or XS Engine) is a lightweight web and application server embedded into SAP HANA which includes configurable OData(XSODATA) support and server-side JS(XSJS) execution.
SAP HANA Extended Application Services(SAP HANA XS) provides a comprehensive set of embedded services that provide end-to-end support for Web-based applications. This includes a lightweight SAP HANA XS web server, configurable OData support(XSODATA), server-side JS execution(XSJS) and full access to SQL and SQLScript.
The SAP HANA XS server allows clients to access the SAP HANA system via HTTP. Controller applications can run completely natively on SAP HANA, without the need for an additional external application server. The application services can be used to expose the database data model, with its tables, views and database procedures, to clients. This can be done in a declarative way using OData services or by writing native application-specific code that runs in the SAP HANA context. Also, you can use SAP HANA XS to build dynamic HTML5 UI applications.
In addition to exposing the data model, SAP HANA XS also hosts system services that are part of the SAP HANA system. No data is stored in the SAP HANA XS server itself. To read tables or views, to modify data or to execute SQLScript database procedures and calculations, it connects to the index server (or servers, in case of a distributed system). From SPS 11, SAP HANA includes an additional run-time environment for application development: SAP HANA extended application services (XS), advanced model. SAP HANA XS advanced model represents an evolution of the application server architecture within SAP HANA by building upon the strengths (and expanding the scope) of SAP HANA extended application services (XS), classic model.
