An apparatus comprises at least one processing device comprising a processor coupled to a memory, with the processing device being configured to receive in a microservices mediation layer a plurality of event notifications for respective internal events generated within an application, to extract information comprising at least a subset of an entity type, a key and an action from each of the event notifications, to issue at least one corresponding request to one or more microservices based at least in part on the extracted information, to prepare at least one message based at least in part on one or more responses received from the one or more microservices, and to publish the at least one message to one or more message consumers. The microservices mediation layer is illustratively configured to permit seamless switching between synchronous and asynchronous canonical message formats.