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Considerations when choosing between IMAP or POP3

Help : IMAP or POP3 ?

Since SMTP's main function is different altogether, the dilemma of choosing the better protocol usually involves only IMAP and POP3.

Here are some of the things you will want to put into consideration:

Server storage space

A server with limited storage space is one major factor that may force you to favor POP3.
Since IMAP leaves messages on the server, it can consume storage space faster than POP3.

Advantage: POP3

Anytime, anywhere access

There's one good reason why IMAP was designed to store messages on the server.
It's meant to enable retrieval of messages from multiple devices; sometimes, even simultaneously.
So if you have an iPhone, an Android tablet, a laptop, and a desktop, and you want to read email from any or all of these devices,
IMAP would be the better choice.

Advantage: IMAP


If you access email messages from multiple devices, you'll likely want all devices to reflect whatever action you performed on one device.
For instance, if you read messages, A, B, and C, then you'll want those messages to be also marked as "read" on the other devices.
If you deleted messages B and C, then you'll want those same messages removed from your inbox on the other devices as well.
If you moved message A to another folder ... well, you know what I mean.
All these synchronizations can only be achieved if you're using IMAP.

Advantage: IMAP

Because IMAP allows users to arrange messages in a hierarchical fashion and place them in folders, it's certainly better at helping users organize.

Advantage: IMAP

Computational overhead

Of course, all that IMAP functionality comes at a price. It's arguably more difficult to implement and certainly consumes a lot more CPU and RAM, especially when it performs those synchronizations. In fact, high CPU and memory usage can happen at both the client and server side if there's a ton of messages to sync.

Advantage: POP3


This is one concern that would weigh heavily on end users who frequently deal with confidential information.
These users would prefer to download all email messages and leave no copies behind on the server.

Advantage: POP3


Whereas POP3 downloads all mail messages upon connection, IMAP may optionally download just the message headers or certain portions and leave.
For example, the attachments on the server. Only when the user decides the remaining portions are worth downloading, will those portions be downloaded.
In this regard, IMAP can be considered faster.

However, if all messages on the server are supposed to be downloaded every single time, then POP3 would now be faster.

Advantage: Depends on the situation

As you can see, each protocol has its own advantages and disadvantages.

It's really up to you to decide which functions/capabilities are more IMPORTANT to you.

Updated on: 20/06/2022

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