Most programming environments have SSH/SCP libraries. If you want to maintain a simple upload/download model, SCP is the way to do it.
It's not entirely clear to me that an FTP-style upload/download model is best here, mainly because I haven't the faintest clue what an "email appending company" does.
It's not entirely clear to me that an FTP-style upload/download model is best here, mainly because I haven't the faintest clue what an "email appending company" does.