That would be something you configure on the mail client. It's up to the mail client to store the sent mail into your mailbox's sent items folder (using IMAP, EWS, EAS, MAPI, whatever protocol you use).

It's not related to the SMTP submission itself.

There are maybe some clients that you can configure to store the sent mail in a specific folder based on rules, but to be honest I never looked if such an option existed.

Kind regards

Actually emClient seems to have this option though. I just tried it.

And after a test, the sent mail was indeed moved to the "Wonderful" folder.

Kind regards

I used Eudora via POP for thirteen years and relied on that functionality with the myriad folders I kept. But those single-client days are long gone. IMAP means that customers (including myself) can use an email app on their laptop, desktop, phone, tablet, and of course webmail. There is no reliable single-app filtering like in the old days. There is also no longer a single "sent" folder, as each app uses a different folder, like Sent, and Sent Messages, and Sent Items.

The only thing that's consistent between all of these is the connection to the SMTP server.

SmarterMail has Content Filtering built in, and should be easy to include in that code's scope.

Mik,

I've always been able to coordinate all my sent folders and junk folders amongst all my clients and webmail by altering settings where needed. I keep one sent and one junk for each account.

Eudora. That brings back memories.  "Why I Live at the P.O."

Patrick, of course. An advanced user, when installing those apps, can change settings. But the average user, and I include myself in that category, won't bother. It would be up to the email industry to agree and coordinate on that aspect. Inbox is /inbox. Sent should be /sent. Period.

In any case, there has to be a solution. All emails are sent using SMTP, so there's a common hook in there somewhere, and being able to apply Content Filters on that at the server level, where it already exists for Inbox, would be ideal. When creating filters, we can specify those various sent / sent items / sent messages folders, too, if that makes it easier. Perhaps there could be one configuration setting for Content Filters as a whole: set which folders to look at for all filters, not just Inbox by default.