SMTP stands for Simple Mail Transfer Protocol, and its Primary function is to manage email sending, receiving, and relaying. Your emails are simply strings of text; SMTP assists servers and email clients in categorizing and organizing the data you transmit. When someone sends an email, they split the sender, recipients, email body, and title heading into parts. It is only applicable to outgoing emails. SMTP is also in charge of establishing contact between servers. The first server identifies itself and sends the kind of action it will carry out only after the second server has authorized the action is the email sent. Finally, SMTP relay simplifies everyone's life as marketers by doing all of the heavy lifting in the background, allowing everyone to spend more time producing content and expanding our contact lists.While sending singles emails, the messages get routed via SMTP and the POP3 server of your email recipient before landing into the inbox. However, when you send emails in bulk, covering the journey from sent to received isn't easy. The emails server comes with certain limitations on the number of emails sent in a day or hour. Furthermore, the bigger the campaign, the lower rate of delivery may get. Ergo, the selection of the right smtp server for bulk email becomes critical for the success of your email marketing campaign.