The recurring integrations scheduler, also known as QuartzAX, is a solution that can be used in on-premise, file-based integration scenarios for Dynamics 365 for Finance and Operations. This is a free open source, community-driven sample app available on the GitHub. 

The following diagram has been taken directly from the tools' wiki page and explains the conceptual architecture of the tool:

The recurring integration scheduler uses Finance and Operations batch data APIs to enable recurring data import and export scenarios. This tool can be a good implementation accelerator to use during the implementation phase of the project for data migration, ad hoc file integration needs, and as a proof of concept integration solution.

Integration planning and having a good strategy are key to a successful integration solution and the overall success of an implementation project. The next phase after you completed the integration strategy and planning is integration design and development.