1. A computer-implemented method of executing an enterprise application, the method comprising: receiving, by a computer, an external request from a client device for a service provided by a runtime engine of the enterprise application, wherein the runtime engine runs on the computer; automatically selecting, by the computer via the runtime engine, a script from a plurality of scripts saved on a database based on the external request; referencing, by the computer via the runtime engine, one or more tags stored in a tag library saved on the database that are called by the selected script, wherein the one or more tags in the tag library define commands of the plurality of scripts and call one or more granular services of the enterprise application; loading, by the computer via the runtime engine, the selected script and the one or more tags referenced by the selected script; and executing, by the computer via the runtime engine, instructions of the loaded script based on the one or more tags to provide the service to the client device as requested by the external request, wherein the selected script is updated in the database after executing instructions of the loaded script.