Write files to MBL remotely?

My use case is that I have a local folder on my computer which I want to keep in sync with a folder on my MBL when I’m connected to the internet but not on the same network as the MBL.

I’m a developer and had hoped to be able to do it via an API, but having looked through the documentation it doesn’t look like any of the API functionality covers the MBL, only newer devices.

I guess plan B is FTP but I don’t know how I would go about getting that set up to access locally let alone remotely.

Just wondering if anyone out there has any experience of doing this?