There is no need to send an email to verify whether a recipient exists or not. You can ping an email box by hand or opt for a ready-to-use email verifier
There are two major types of emails: transactional and marketing. However, they have numerous subtypes. Check out the real-life examples of those.
An SMTP server is a computer or app that is responsible for sending emails. Find answers to frequently asked questions about SMTP servers in this blog post
GDPR lays out the principles of personal data protection. We collected and answered the top 11 questions about how GDPR affects email marketing
Having multiple SPF records for one domain is a bad practice. Learn how to convert this for your own benefit and explore useful tips to set up an SPF record
Of the following MTAs of Postfix, Exim, and Sendmail, which would suit your project? Check out the selection criteria and explore which MTA prevails.
Google Analytics is a powerful tool for click tracking. You can also use it to track email opens for email campaigns. Here is a tutorial on how to do this
The list-unsubscribe header is an unsubscribe link displayed in the email header. Explore its benefits and how to set it up in this blog post.
There are two email transfer methods: SMTP relay and Web API. Check out the pros and cons of each of them to know which one is the best for your project.
550 5.1.1 User unknown is a server error response code to RCPT TO command. Learn what it means, how to fix and avoid this issue on different servers