I understand from the mail documentation that GAE is limited in who mail can come from when sent by the app. There are options for receiving incoming mail on a different domain (basically having it forwarded) but are there any options for sending mail from an app. Ideally i’d like my app to be able to send mail from a different address for each user in my app, so that when replies were received I could match them up to the user that sent them.
I’d ideally like the emails to come from <userid>@<custom.domain>.com but could live with being able to send them from <userid>@app-id.appspotmail.com.
Do I have any options here?
As far as I know, your only option would be to communicate with an external server that via a URLFetch. The external server would be responsible for sending and receiving email through the usual means and providing a web service interface that your AppEngine app could use.