If you are using /usr/sbin/sendmail style delivery, for example via the built-in postfix implementation on macOS and many linux-like systems, it's fairly easy to configure postfix to rewrite absolutely everything to go to your own email address. This can be quite helpful during development, because not only do you get to see the emails as they are delivered, but you can also worry less about sending development emails out to random addresses around the world. (Look into "recipient_canonical_maps")