I have had my own domain for a couple of decades. Never had any problems with people receiving emails from me until recently. Through a number of tests, I discovered my domain was not black listed but instead the SPAM filters on certain providers would put my emails into SPAM until the recipient explicitly went into the mail browser and selected not SPAM for my account. See attached from [http://example.com https://glockapps.com/] One of those providers is Rogers here in Canada which is using Yahoo for email. The users addresses are in @rogers.com. I happen to have a Rogers account as well as my private domain which is my default in Thunderbird. What I would like to do is have a plug-in that would look at all the email addresses I'm sending to. If a particular domain match is found, Thunderbird would change to use a different outbound account. For example, if I was sending from paul@mydomain.net, and a @Rogers destination was found, TB would change to send from my paul@rogers.com account. At this moment, I doubt if there is a plug-in to do this. I have never explored writing a TB plug-in so wanted to ask if there are events hook onto when SEND is pressed to do what I want? Thanks