Some mail clients let you deliver mail to a script

https://serverfault.com/questions/506894/how-to-route-email-...

In that case you'd need to run a mail server where you install a script. I've done it with qmail and postfix but I haven't run my own mail server for a long time.

Another option is to use an existing mail server but write a script that polls the mail server with POP or IMAP.

Today I'd consider doing it serverless with something like

https://aws.amazon.com/about-aws/whats-new/2019/02/trigger-a...

So far as the "stack" I would go with any mainstream platform, mostly driven by what you like. You could certainly do this with Python, Java, .NET, etc.

I'd use the inbound feature APIs of Mailgun/Sendgrid/Postmarkapp. They take care of receiving and parsing and can call a URL on your server with new email content. At least in the beginning you can concentrate on the business logic ("accurate response") and don't have to worry about character encodings, parsing attachments or such.

This is a perfect response. I'm biased towards SendGrid as I work there :)

You can totally do exactly what OP wants. Use the inbound parse webhook, get mail forwarded to your HTTP webhook/endpoint, do whatever you want, and then you can even reply using the email API of the provider. No reason to sweat the mail server stuff.

I appreciate the both of you. Will definitely jump on SendGrid and get started.