What are your latency and bandwidth requirements? How big are the files? If you are already looking past obvious TCP-based choices like HTTP and FTP, you might

What are your latency and bandwidth requirements? How big are the files? If you are already looking past obvious TCP-based choices like HTTP and FTP, you might be interested in FASP/Aspera https://en.m.wikipedia.org/wiki/Fast_and_Secure_Protocol https://en.m.wikipedia.org/wiki/Fast_and_Secure_Protocol Edit: I’ll leave it here just in case it is useful for others but it may or may not be embeddable into your app, especially on the phone.