No, you can use any SMTP/IMAP/POP3 capable client instead of using their web interface. https://protonmail.com/support/knowledge-base/imap-smtp-and-pop3-setup/

No, you can use any SMTP/IMAP/POP3 capable client instead of using their web interface. https://protonmail.com/support/knowledge-base/imap-smtp-and-pop3-setup/ https://protonmail.com/support/knowledge-base/imap-smtp-and-... But you are still making an IP connection. JS/no JS is not relevant to this discussion.