SpamAssassin - Use this program to "Unspam" your mailbox(es).
Charles Proxy - HTTP proxy / HTTP monitor / Reverse Proxy
Rspamd - Rspamd is an advanced spam filtering system that allows evaluation of messages by a number of rules...
Wireshark - Wireshark is a network protocol analyzer for Unix and Windows. It lets you capture and interactively browse the traffic running on a computer network.
Oikik Antispam - Oikik is a cloud-based email filtering service that works with your existing email service.
Postman - The Collaboration Platform for API Development