If your website has features that depend on email communication with your customers, you will want to consider using some sort of “transactional email” provider. Transactional email is defined as email that is generated at the request or as the result of an action(s) of a visitor to your website. Often, this will be the purchase of a product from your online store but it could be other actions as well.
The delivery of this type of email is critical to both you and your customer. Using the default WordPress method for sending email often results in email being flagged as “spam” by many filtering applications. Using a SMTP plugin and a “real” email account to send transactional email may still not be sufficient to guarantee delivery.
The use of a transactional email provider such as SendGrid greatly simplifies the job of ensuring delivery. SendGrid sends email using it’s own email servers and works diligently to ensure that they are not blacklisted. SendGrid also logs delivery failures with detailed diagnostic information.
Best of all, SendGrid has a free tier which allows for up to 100 emails per day (~3,000 emails per month). This is perfect for the small business or non-profit with modest transactional email volumes.