Is there a program to monitor/backup files with .txt exntesion into a remote backup service?

I have multiple remote machines on which I run a program to process some stuff and save into .txt files.

I need a program that monitors a folder and its subfolders for any added .txt files and then upload those to a remote backup. I do not mind backing up to cloud services as long as the client does not panic as soon as I log the account from multiple machines blocking access until I provide OTP.