There would be other ways to clog the system using trashmail providers but thankfully no student cared enough for that yet
Am I crazy or just missing some super obvious gap with this path?
If you can convince everyone to trust you, and your service, and that it'd be worth it for mail providers to do all that work on their end on top of everything they're doing currently to prevent spam, it really could improve deliverability.
You'd have to do a lot if work to validate new senders long before they send their first message and you start getting complaints or else you're just letting spammers pay you to completely bypass every mail provider's spam filters until they finally get blocked and have to create a new account with you under a different company name.
Why would you need to do that? Just work with those that'll pay you for it. The others won't care as they'll just ignore the header.
I suppose that really you'd be able to get a lot of utility by convincing just a handful of very popular email providers (gmail) to trust that your service will never be used to send spam (or that they should let spammers who slip by you right past all of their spam filters). The more email providers you can get to use your service though the more you could charge the mass mailers for guaranteed message delivery.
Such a service could lead to two very bad outcomes though. Parents being told that if they want to get email from the school they'd better sign up for an email account at one of the few supported email providers (gmail) and/or (if it becomes successful) any sender who isn't paying for the privilege of sending email being treated like a spammer.
This is often not a non-sense complaint. A lot of newsletter signups are still via pre-selected checkboxes that are easy to miss.
That would get you added to a "never block mail from this domain" whitelist that had higher precedence than everything else.
Scandalous, it's almost as if the established major providers have a financial interest in making it difficult for smaller providers and individuals to send mail using their own domains!
During the pandemic we had a lot of problems with the confirmation email for our 5000 T.A. in the virtual campus of the university. I had to guess what was happening because I was not part of the administration team, just collecting forwarded messages form the T.A and guessing:
* Gmail: Most of the time it works.
* Yahoo: The server receives a few hundred emails per day and the other are delayed. These were confirmation emails with half an hour tolerance, if they were lucky to pass the next day they were not useful. (After a week the sending server stops retrying.)
* Hotmail: Sometimes the email is received and sometimes it just disappears. No spam folder. No bounce email. It just evaporate. (Try sending an email from hotmail to the no-reply address and cross your fingers.)
* Others: No enough data to have a good guess.
Gmail will do this too. Happened a few months ago with a single (important) message from a private individual sender on Hotmail, one unknown to my Google account. The fix was adding the Hotmail address to a Google Contact.
And Yahoo is the Single worst email service to send to. I have AFP, dmarc, dkim, reverse dns for the Mailserver and have tested the wording with multiple mail testing services to make sure it doesn't have keywords that get automatically flagged
And yet after like 50 emails to parents with yahoo email addresses they are giving me errors because of "unusual volume of emails from your domain"
There is no form, no human to talk to and they just block you.
Angry parents come to me or course because they never redeived the activation link