Thank you for contacting Panic.

Technically, yes, there is a way we can accomplish this, with a few caveats 😅. 

One note, Panic Sync was designed to be a personal backup for one user. It can, of course, be used by multiple users on different computers, and this method I think is the best way to prevent any weirdness of syncing across multiple computers.

 Bear with me, this may be a lot of info, but I hope it'll help! 

First, I'd recommend keeping a manual backup as a master list that can be restored manually, unfortunately, there is not a way to restore from Panic Sync.

1. In Transmit, from the Servers menu bar > at the very bottom is an option for “Export”: 

You'll have an option here to save encrypted with or without passwords:
Transmit stores the passwords in Keychain Access on the given machine. Which means that if the export and import of this file will happen on the same machine, using the `Unencrypted without passwords` will work, as keychain will step in with the passwords. 

If you'd need to move the servers to a different computer, that's where I'd recommend using the `Encrypted with passwords` option,  as the passwords will be saved securely with the export file. Now, importing this file onto a different computer will also import the passwords.

Okay, now that we have that out of the way: 
Is it possible for security reasons to back up the sync data once?
If someone overwrites the data, is there a history that can be restored? 

The best bet here, is setting a policy in place of: 
1. Signing in to Panic Sync to replace all data on the device from Panic Sync 
2. Then once that's synced down, signing out of sync 

Signing out, will prevent any syncs from happening back to sync.

But every time you sign in, there will always be a way to choose "Replace all data on device from Panic Sync", which will only bring data down from sync and not up to replace data on Panic Sync....that was really wordy, I'm sorry ha ha

Here's what you'll see when you sign into Panic Sync in Transmit:

1. There are two repos that Sync can save to: 
— Transmit & Nova
— Transmit Only

I'd recommend choosing Transmit Only, but we'll come back to this:

The next screen is the important part: 

The first time syncing, we can choose "Replace All Data in Transmit On This Mac": This means that any data in Transmit will be erased and replaced with the servers in Panic Sync. Once the sync happens, the user can sign out, preventing any changes going back to the Panic Sync server.

Every time someone logs into Sync, they can always choose this option. So if there's any ever changes that other users need to have, they can sign, choose to replace all data, bring down the changes and sign out. 

*** This is also why the manual backup comes in handy! In case anyone ever does sync up, there's a way to restore it from the master backup file. Which I can provide more info on in a different email if you'd like! 

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Regarding the two repos:
— Transmit & Nova 
and 
— Transmit Only

These are two separate repos, whomever is managing sync could use the two repos as a safeguard as well. 

If you sign in, choose Transmit & Nova, sync and then sign out and do the same with Transmit only, that means there's now two different repos. In the event an issue happened on one of them, we could always restore from the other repo as well. I guess this is a bit of a workaround to the restore option! 

Sidenote: Thank you for sticking with me 😅, I took the opportunity to be a bit more verbose than I normally would. But now I'm going to take this and create a very long-overdue library article! 

Any further questions, please let me know!