Content Sync provides a lot of customization options through the Flow configuration you can create per site. There’s also an Advanced section available for even more options at the last page of the Flow form.
We already support all the most used contrib modules’ fields and entities (see here for a full list). To see if everything you need for your site is supported you can head over to the Compatibility tab that’s available at the Content Sync configuration pages after installing the module.

If you have custom entity or field types that you need support for you can also create your own Entity Handler and Field Handler to tell Content Sync how to serialize and deserialize the data. We also trigger Drupal events before and after every push and pull to allow you to customize the data before it leaves and before it enters your sites and to make additional changes to created or updated entities.