Maropost for Marketing's API via SMTP enables transactional messages created in your platform to be sent to Maropost which will in turn relay and send the messages to the intended recipient.
We recommend that you utilize our RESTful API for sending transactional messages. However, we provide this alternative protocol API for clients having legacy systems which were developed to create and send transactional messages directly to the end recipient.
The advantage of using Maropost’s SMTP API is to take advantage of Maropost’s sending reputation to ensure the highest deliverability rate for these all-important types of messages.
The SMTP API is also the only means that enables file attachments up to 10MB in size to be sent as transactional messages. While sending file attachments in transactional emails is no longer considered best practice (file attachments — especially PDF file are now the Number 1 vector for viruses,) this capability exists to support legacy systems.