Google's has free IMAP/POP/SMTP service but there daily email limit is 100/day. ProtonMail dosn't have any free IMAP/POP/SMTP services and there daily email li

Google's has free IMAP/POP/SMTP service but there daily email limit is 100/day. ProtonMail dosn't have any free IMAP/POP/SMTP services and there daily email limit is 150/day. So if you don't have many subscribers you should be fine. But you might be better off hosting your own small email server. You'll have much more control over your emails. Good job coding "nwsl" in python, but you can code even lighter version with simple bash script.