Hot answers tagged email-client
We have templates built into PostageApp that you can add message variables to (for customer name, etc etc) and you send the messages by sending JSON to our API via HTTP POST. You'd have to build the scheduling on your end, but is this something you were looking for? Let me know! (Full Disclosure: I am the Product Manager for PostageApp)
So, you are effectively looking for a web-based version of Thunderbird. Well, it seems that someone has started an open-source Google Code project named webtdb with this exact purpose, but it does not seem to have progressed very far yet. If you are willing to consider non-free closed-source solutions, then Outlook Web App (part of Microsoft Office 365) ...
You may find what you are looking for at Outlook.com. Here is a view of the Email Options/Settings panel:
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