The party line.
Most transactional email goes out on a shared line. It's fine until the morning it matters.
In the early days of the telephone, out in the country, you didn't get your own wire. You got a party line. Four or five houses on one circuit. If the neighbor was on, you weren't. You picked up the receiver, heard someone else's conversation, and waited.
It was cheap. Everyone accepted it. Right up until the barn was on fire.
That is how most transactional email is sent today. Not because anyone chose it. Because it is the default, and the default is free.
Here is what the default looks like from the inside. A free tier lets anyone in with an email address. The mail goes out from a shared pool of reputation, through queues everyone shares. The good senders and the bad ones sit on the same wire. The inbox can't tell them apart by looking, so it judges the wire.
Then someone on your line does something stupid. A bought list. A phishing kit. A signup form with no rate limit. Their bounces count against the pool. Their complaints count against the pool. And on a Tuesday morning your password reset lands in spam, or doesn't land at all, for a reason that has nothing to do with you.
You didn't do anything wrong. You shared a line with someone who did.
The private line
Transmit is the private line. That is the entire idea, and everything about the product follows from it.
There is no free tier, so there is nobody on the line who didn't put a card down and verify a domain they own. You send from your own domain, and only yours, so the reputation the inbox sees is the one you built. Every message is screened before a provider sees it, so the accounts that exist to burn a domain and leave are stopped at the door instead of reported to us later. Bounce and complaint rates are enforced on every account, ours included, because a bad list gets paused before the inbox notices it.
We can't promise nothing will ever break. Nobody can, and the ones who say so are the ones you find out about on a bad morning. What we can promise is that when something goes wrong on your line, it went wrong on your line. Not on a stranger's.
Pick up the receiver. Dial tone.