SMTP vs IMAP
SMTP, which stands for Simple Mail Transfer Protocol, along with IMAP (Internet Access Message Protocol) are the two mechanisms that are used in sending and receiving email messages. The main difference between the two is the function that they play. SMTP is the protocol for sending email whether it is from the client or in between servers for propagating the email towards the intended destination. In comparison, IMAP is a protocol that deals with managing and retrieving email messages from the server. So if you are using email, you are probably using both protocols even if you don’t know it.
Another key difference between SMTP and IMAP is where it is used. IMAP is used only between the client who is retrieving the email and the server where the emails are stored. In contrast, SMTP is used by the client to send emails to a server but it is also used by servers to push the email to another server; especially true when the sender and recipient do not subscribe to the same service provider.
IMAP is only one of the many protocols for retrieving email, another one is POP3. These two are the most popular protocols for retrieving email with IMAP being the more powerful of the two. But due to prior support for POP3 in older devices, it is still in widespread use today. SMTP is undisputedly the most prevalent protocol for sending emails. Although there are other outgoing email protocols, SMTP is the most popular and widely used.
For browser based email services, there is really no need to mess with or even know the protocol being used or the exact addresses used for these protocols. Knowing these details only becomes relevant when you are using another client like Microsoft Outlook or Mozilla Thunderbird to send and receive your emails. Depending on your service providers, you can get two relevant addresses; one for SMTP and another for either IMAP or POP3. These addresses should be configured correctly into your client or you would not be able to receive emails, send emails, or both.
Summary:
1.SMTP is used for sending emails while IMAP is used for retrieving emails
2.SMTP is used between servers while IMAP is only used between client and server
3.SMTP is the prevalent protocol for outgoing email while IMAP is only one of two prevalent protocols for email retrieval