SmartSync is an on-premise tool that can sit between Zahara, Sage & SmartInvoice. The diagram below explains how this works:
SmartSync will not only sync suppliers and coding from Sage, it will also listen for new invoices selected for export in Zahara. Used with SmartInvoice, it can also upload invoices from the desktop into Zahara.
To install SmartSync, head to the Business > Settings> Integrations page and select SmartSync 50. You will be promoted to download the relevant version and offered to download and install SmartInvoice as well.
Please read the setup guide in the SmartSync section of the Knowledge Base