Also, fuzzing is becoming quite popular. It’s a technique that automatically detects vulnerabilities on a binary. Though, it is computationally intensive, so I would love to the emergence of a peer-to-peer project that allows anyone to contribute by testing open-source software.

I ended up setting up a postal server on my vps (see here). Their docs are pretty easy to follow through and it’s probably the cheapest option (assuming you already use the and have a domain).