Although Keepmark do not provide any repository sync service, you can easyly synchronize your repositories between devices using 3rd party providers, like Dropbox, or GDrive.
Keepmark keeps your files and data with original format. Repository is a regular directory with list of files and subfolders, so you can synchronize all repositories using any synchronization tools. You can even access your
files without Keepmark (but why sombody would like to do that when Keepmark is nearby).
This is one of my main assumptions when working on Keepmark - files and data can not be trapped in a format unavailable to other applications.