Email deliverability, as the term suggests is the ability to deliver emails to the recipient's inbox. This is one of the key metrics that marketers take into account while measuring the performance of their email marketing efforts.
Most email marketing tools promise an email deliverability of 95% and upwards. Some of the common issues that plague delivery are varying ISPs which are not whitelisted, spam, bulking issues, and throttling among others.
Marketers can take additional measures to ensure better email deliverability. They can do this easily by sending from a free domain address, limiting the number of images in the mail, using genuine headlines instead of spam content, providing an unsubscription button in emails, using custom authentication, and double opt-in. Basically, doing everything to make it seem less spammy and making it harder for bots to submit spam email IDs.
The emails that don’t get delivered get accounted as bounces. If it happens because of a permanent reason, it is a hard bounce or else, it is termed as a soft bounce in case of a temporary issue.