E-mail Explained: The Difference Between IMAP and POP

by Tom Harrison in office productivity

While IMAP and POP are both methods of checking e-mail, they are very different from each other. Each has its advantages and disadvantages, and your decision between the two will have a drastic effect on how you check your e-mail.

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During the account setup process of desktop e-mail clients (e.g. Apple Mail, Microsoft Outlook), there is a certain question that confounds many computer users. Whether you use a PC or a Mac, whether your service is provided by Google, Microsoft, or your ISP, you cannot avoid this question. IMAP or POP?

How E-mail Works

Your inbox lives on an e-mail server, which is a computer out there on the Internet that is always on and ready to accept messages from everyone who is trying to get in touch with you. Software such as Microsoft Outlook is referred to as an e-mail client – a program that gets your e-mail from the server and shows it to you. An e-mail client also allows you to compose messages, and then hands them over to your e-mail server for delivery. POP and IMAP are two different ways in which this client-server interaction takes place.

How POP Works

A POP email client downloads all of your e-mail from the e-mail server to your own computer, then deletes it from the server. Once you have checked your messages via POP, those messages no longer live on the server – they exist only on the computer from which you checked your e-mail.

POP is really only sufficient if you have one dedicated computer from which you check e-mail. Let’s say you check in with computer A – computer A fetches all your e-mail from the server, then removes it from the server. If you were to then check your e-mail with computer B, your inbox would appear to be empty because all of your e-mail was previously transfered to computer A.

How IMAP Works

An IMAP client synchronizes the e-mail on your computer with the contents of your account on the e-mail server. IMAP copies messages from the server instead of deleting them; when you use IMAP, an e-mail message is only removed from the e-mail server when you choose to delete it. Instead of moving messages from the server to your computer, IMAP synchronizes your computer with the e-mail server.

IMAP is a good choice for people who need access to their e-mail from home, the office, the road, and anywhere else. If you were to check your e-mail from three different computers via IMAP, all three of those computers, and the e-mail server, would contain all of your e-mail. If you chose to delete a message from computer A, it would also be removed from computer B, computer C, and the e-mail server.

Which One?

POP would be a good choice for someone with limited Internet connectivity or a small allotment for e-mail storage, and who is also comfortable with checking their e-mail from only computer. If this describes you, then you can take advantage of the fact that POP will download all of your e-mail in one shot and then delete it from the server, freeing up storage space and network resources.

IMAP is a good choice for those who require access to their e-mail (especially saved messages) from wherever they happen to be at any given time. No matter how they get online and regardless of what computer or gadget they use to check their e-mail, IMAP users will always see the same messages. IMAP is also efficient at managing large volumes of e-mail — at first, only minimal information such as the sender, subject, and date/time are downloaded. Once you choose to read a message, the rest of the message body is then fetched by your e-mail client.

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