1. A method comprising: executing, by an orchestrator, an end-to-end process across a plurality of applications, wherein the executing of the end-to-end process by the orchestrator comprises executing flow logic by the orchestrator, the flow logic according to a data model defining arguments to include in interactions between the orchestrator and each of the plurality of applications; and exchanging, by a message broker, messages among the orchestrator and the plurality of applications, wherein exchanging the messages comprises the orchestrator sending calls to respective applications of the plurality of applications, the calls delegating tasks of the end-to-end process to the respective applications, and the orchestrator reacting to an event or call from at least one application of the plurality of applications or another source through an interface of the message broker.