Ensuring high deliverability in email is no walk in the park. As a high-volume sender of email, there are many things to take in consideration, especially with cybercriminals keeping a fast pace in innovation.
Make no mistake, deliverability is of highest importance to anyone sending email, let alone the high volume senders. When you get the information from your servers that a certain percent of sent emails were accepted by the receiving servers you still have no idea what happened after that. No confirmation of emails actually reaching inbox means they might just as well be laying in the spam folder. The SMTP transaction is logged as ”250 OK” as long as the server didn’t reject the email. To make matters even worse, different ISP’s may treat email differently, putting more responsibility on the sender to do their homework as neat as possible.
Pay attention to encryption, as it no longer is as security measure only for the selected few, but becoming the standard. TLS/SSL and DANE are your friends and will keep your information private.
Be protective of your IP addresses reputation, they can make or break your deliverability. ISP’s acts as proxies for recipients, meaning they will take reputation very seriously. Take in consideration that sending unsolicited email may harm your IP reputation, and authenticating your email with SPF, DKIM, and DMARC will help keep out scammers who are most often ahead of ISP’s and senders technology.