What is IMAP vs SMTP?

What is IMAP vs SMTP?

Let's take a quick look at what is Email and why it is used.

An Email is a short message between people, for example a friend asks if you're fine today or I send you the photos of my latest trip as she has forgotten to send them yesterday. However, over time this type of communication has become much more of an enterprise way of using email to communicate with other companies or departments and it is here that the importance of protocols like IMAP versus SMTP really comes into focus. IMAP is one protocol type (like SMTP) that allows you to move email from one server to another and SMTP is often used in its basic form when an email is sent by an email client. To make it as simple to read and understand we will break this down in the following sections. I will give an example here on Gmail but this applies to IMAP and SMTP so it doesn't matter where you are sending your email from.

How do these two protocols differ? The first thing you would be seeing from this discussion would be SMTP is a protocol and IMAP is a protocol. Technically this is true however, there are some differences in the way these two protocol types operate. Both are used to send email messages from your computer but when an email message goes across the Internet or between different domains its data is encapsulated. With SMTP you encapsulate the message and you can tell this by the .SMTP domain in front of the email address. In a more simple explanation this means if a sender emails you and their address begins with s he would send the email in a smtp format and if the receiver's address begins with a .mailbox name then the email was sent in an imap format. This is to say in real-time and without going into too much technical jargon is SMTP would encapsulate the email when it is first being sent across the internet to you and after it is received you would un-encapsulate it and then send it again to the appropriate recipient mailbox for him to receive it and this will happen in real time. The following diagram shows how the sender's address would be SMTP encoded or SMTP protocol.

What is the difference between SMTP and POP3?

The difference is that email messages are sent and received using SMTP.

While your provider sends out an email message with the correct headers to ensure delivery, in reality you receive the email directly from your ISP (or possibly from another email server).

A POP3 email account has messages saved on your PC, not on an email server. You download them to your computer as they are received.

This may be a bit difficult to see if you are only used to Outlook, but if you switch your email client to thunderbird or something similar, then you'll notice the difference.