13. A computer system comprising: at least one memory storing instructions; and at least one processor configured to execute the instructions which, when executed, implement multiple client engine, a user interface (UI) runtime server client, a repository and a customized view engine, wherein: each of the multiple client engines is associated with a different customer and each of the client engines is arranged and configured to run on a client device on the client side of the network as a plug in application to a browser application without using a Java stack and to initiate requests for one or more UI models and to initiate requests for one or more host-based applications, receive the UI models in response to the requests and interpret and render the UI models at runtime; the UI runtime server client is located on a server on the server side of the network and is arranged and configured to interface with each of the client engines to receive and process the requests for the UI models from the client engines and to receive and process the requests for the host-based applications including a common output for the host-based applications; and the repository is located on the server on the server side of the network and is arranged and configured to: store the UI models and to store the host-based applications, and interface with the UI runtime server client to deliver requested UI models to the UI runtime server client for interpretation and rendering by a requesting client engine, wherein each of the client engines further comprises the customized view engine that is configured to provide a customized output of the host-based applications to a particular user, wherein the customized output is different from the common output of the host-based applications received from the UI runtime server.
17. The computer system of claim 13 wherein the customized output for the particular user includes at least one custom pane.