Rate-limiting would be interesting. If the cost of the service was specifically high enough to be unscalable. Like, $10 per month and you can send 200 emails per day. That’s expensive compared to anything else but fine for personal use.
fastmail already is available for $10 per month, so I guess problem solved?
Do they handle a send-only smarthost configuration that allows arbitrary from addresses within a domain?
As far as I can tell, yeah.
Pretty soon email will require stamps, like paper mail. I wonder if they will sell forever stamps?
Jk, I just thought it was funny that we pay for services which were always seen as a free alternative to paper mail and stamps were a thing of the past.
Proof of Work basically was invented to cope with email spam. That's more or less a stamp.
If you have a KvK in The Netherlands your PII details are public, and you will start receiving physical spam from companies despite such spam not being free to send. I never receive spam from individuals though; only companies.
On top of that, the costs of electricity are not the same everywhere (they are very expensive in The Netherlands, for example, than in the USA, and China is very cheap). Nor is it widely stable available everywhere (examples include India and Africa). Proof of Work is basically a waste of energy as well.
How about https://postmarkapp.com/ ? It is more tailored to "transactional emails", but seems pretty close to what you describe
But this is exactly what I use mailgun for. The free price point kind of enforces that.
Maybe it's just been so long I'm whitelisted?
More likely you actually set it up correctly, with DKIM and stuff, and the parent didn’t.
Such a product would need to have a ToS that states it can only be used for low volume personal and business correspondence, and have per-account rate limiting to enforce that. Doing it this way is necessary to avoid having mail treated as bulk.
I've tried relaying through mailgun to get mail to outlook.com, it does not work.