[svapnil]

I never knew about HL7, thanks for sharing.

I agree that simplicity and open standards will win. SFTP is straightforward and has worked well in the past. In banking and finance, SFTP is what powers most programmatic corporate banking. Eventually, I think we'll see SFTP and message queues (like SQS) used more often as processing speeds up. I believe message queues are what powers much of real time payment processing already (https://news.ycombinator.com/item?id=36805571)

[PaulHoule]

Another approach is to treat it as a document exchange process that is done over REST or RPC. Message queues are attractive though in that they are easily bidirectional.