These are the notes for GoZync 3. Docs for the latest version of GoZync--GoZync 4--can be found here. GoZync 4 is a free upgrade and is highly recommended (hint: it's faster).
GoZync is an unlocked framework for scripting synchronization between FileMaker files, especially between an offline FileMaker Go solution and a hosted FileMaker solution.
If you're new to GoZync, check out this short video of a Zync in action: GoZync Introduction.
Then read about how you can start playing with the already-Zynced sample files that come with GoZync: getting started.
Eventually you can integrate GoZync into your own solution: integration.