SFTP facility for Windows with these requirements

hello

i just would like to ask you guys if you could recommend me an SFTP facility which would satisfy these requirements

1. Transfer of file is in real time. Batch transfer still can be used if interval is no more than 15 mins
2. Transfer of file must be two way.

Server1-outbound folder ---> Server2-inbound folder
Server2-outbound folder ----> Server 1-inbound folder

Basically file transfer is initiated when a file is dropped off at an outbound folder. Server OS of both is windows 2012 server

3. Capability to send email if something goes wrong in file sending

Ive never dealt with SFTP before so I just would like to ask for your opinions.

thanks