[adrian_b]

Any UNIX-derived operating system has some kind of command-line utility for sending email messages (named mailx or mail or Mail).

I do not remember if I have ever used the GNU mail program that is available on Linux, but my e-mail server is hosted on FreeBSD, so I have used very frequently the FreeBSD CLI utility to send e-mail messages from scripts.

Moreover, all FreeBSD servers come configured by default to send automatically a variety of e-mail reports to the administrator, to inform about incidents or statistics, so there are a lot of examples of usage from scripts.

[npodbielski]

Yes I know I am using it. I just think API, built-in API should be standard. Creating separate mailbox for each self hosted service I am running and testing it and making sure it is using TLS instead of STARTTLS or other way around and fixing user name because some services send using domain and some not, and setting correct port because 465 did not work even if it should be using SSL... It is so much hussle. Maybe it was fun when I was doing PHP forms 20 years ago but not now. Now I want to have just API with /mail/send and API key and forget about all of that.