The GAE docs say "do x and we'll send your mail". If we do x and mail isn't sent, then that is a problem.
I agree with you that some measure of notification that there's spam filtering would be good, but it's Google we're talking about. There's spam filtering.
Nonsense! I had no idea this was a feature of GAE. I pay for the use of GAE, and so long as I send less than my quota of emails, it's not Google's business what the content of those emails are.
There's no reason that there should be silent spam filtering on outgoing mail sent by my app. If they suspected that my app was sending spam, they should have notified me and disabled my app. That would have alerted me to the problem.
I find it absolutely abhorrent that Goole would just send private communications sent to me by prospective clients into the trash where they can never be retrieved or restored, and to do so without telling me is beyond belief.
The point: G is accepting cash from one group of people to send a ton of messages (mostly unwanted by addressees) and earning ad dollars from another group to stop unwanted messages.
30 years ago this would be textbook conflict of interest but the 'veil of automation' means we're blind to a lot of unsavory business practices.
That's been tested for and eliminated. My app logs that an email has created and is going to be sent. The send_email function is called to send the email. Then my app logs that the email has been sent.
The emails are sent to addresses hosted at both gmail and outlook. They are not received. They do not appear in spam bins.
GAE has a bounce api that will log if an email is bounced back. In my case, no reports are logged by my bounce handler.
The content of my emails has not changed for 2 years. For 2 years both gmail and outlook received my emails in their inboxes (not spam bins).
Given all this, I'm pretty sure there is an outgoing spam filter.
You are very wrong about this. Senders of email need to make sure they aren't being used for spam or they get blacklisted.
But then they should have notified me: "We suspect you're using the service in violation of our TOS, so you are suspended" or something like that.
I'm paying for a service, they continued to take my money while pretending to provide that service.