OpenUI5 is described as 'Open source JavaScript UI library, maintained by SAP and available under the Apache 2.0 license. OpenUI5 lets you build enterprise-ready web applications, responsive to all devices, running on almost any browser of your choice' and is an app. There are eight alternatives to OpenUI5 for a variety of platforms, including Mac, Windows, Linux, Web-based and Android apps. The best OpenUI5 alternative is DHTMLX. It's not free, so if you're looking for a free alternative, you could try jQuery UI or Dojo Toolkit. Other great apps like OpenUI5 are w2ui, Webix UI , Enact and Kendo UI.