Salesforce to legacy sync

This project was all about bringing the time of golive forward in time. My client was in the middle of a migration from a legacy system to Salesforce. But their legacy system had a lot of third party applications connected to it. The problem was, that my client had a small in house IT department, which did not have the capabilities to migrate all system at once. That's why they needed a synchronization in order to keep all data they create and edit in Salesforce in sync with their legacy system. It was my commitment to develop a generic system for the sync, so that we can extend it at any time, once there is another Salesforce object (database table) that need to be synced. Also, since Salesforce has a limitation on how many SOQL (database) calls may be made within one runtime as well as a daily limit, I always needed to ensure, that I use the least amount of database queries.