Adding "email in" functionality

If you needed to build "email in" or "email to" functionality in your web app with auto-generated email accounts on your own domain, what resources would you use? Is there a service (using APIs or no-code stack) that provides a straightforward protocol or platform for this? Basecamp and Trello provide this sort functionality, where each account provides a user with a custom, private email address they can use to send in data or attachments. https://blog.trello.com/how-to-c... https://2.basecamp-help.com/arti... Thanks in advance for any insight.