POP & IMAP - Which One Should You Use For Your Email?

IMAP is short for Internet Message Access Protocol, while POP translates to Post Office Protocol. In other words, both are email protocols. They allow you to read emails locally using a third party application. Examples of such applications are Outlook, Thunderbird, Eudora, GNUMail, or (Mac) Mail.

The original protocol is POP. It was created in 1984 as a means to download emails from a remote server. IMAP was designed in 1986 to allow remote access to emails stored on a remote server. Essentially, the main difference of the two protocols is that POP downloads emails from the server for permanent local storage, while IMAP leaves them on the server and just caches (temporarily stores) emails locally. In other words, IMAP is a form of cloud storage.

How Do POP & IMAP Compare?
The two protocols are best compared by looking at their most basic workflows.

POP Workflow:

• Connect to server
  
• Retrieve all mail
• Store locally as new mail
• Delete mail from server*
• Disconnect

*The default behavior of POP is to delete mail from the server. However, most POP clients also provide an option to leave a copy of downloaded mail on the server.

IMAP Workflow:
Connect to server
Fetch user requested content and cache it locally, e.g. list of new mail, message summaries, or content of explicitly selected emails
Process user edits, e.g. marking email as read, deleting email etc.
Disconnect
As you can see, the IMAP workflow is a little more complex than POP. Essentially, folder structures and emails are stored on the server and only copies are kept locally. Typically, these local copies are stored temporarily. However, you can also store them permanently.



What Are The Advantages Of POP?
Being the original protocol, POP follows the simplistic idea that only one client requires access to mail on the server and that mails are best stored locally. This leads to the following advantages:

• Mail stored locally, i.e. always accessible, even without internet connection
• Internet connection needed only for sending and receiving mail
• Saves server storage space
• Option to leave copy of mail on server
• Consolidate multiple email accounts and servers into one inbox

What Are The Advantages Of IMAP?
As mentioned in the introduction, IMAP was created to allow remote access to emails stored on a remote server. The idea was to allow multiple clients or users to manage the same inbox. So whether you log in from your home or your work computer, you will always see the same emails and folder structure since they are stored on the server and all changes you make to local copies are immediately synced to the server.

As a result, IMAP has the following advantages:

Mail stored on remote server, i.e. accessible from multiple different locations
Internet connection needed to access mail
Faster overview as only headers are downloaded until content is explicitly requested
Mail is automatically backed up if server is managed properly
Saves local storage space
Option to store mail locally

• Mail stored on remote server, i.e. accessible from multiple different locations
• Internet connection needed to access mail
• Faster overview as only headers are downloaded until content is explicitly requested
• Mail is automatically backed up if server is managed properly
• Saves local storage space
• Option to store mail locally
  
  

What Is The Best Email Protocol For Me?
Obviously, it depends on your specific variables and you probably have an idea of what is best suited for your situation already. The points below should help to make a final decision.

Choose POP If…

• you want to access your mail from only one single device
• you need constant access to your email, regardless of internet availability
• your server storage space is limited

Choose IMAP If…

• you want to access your email from multiple different devices
• you have a reliable and constant internet connection
• you want to receive a quick overview of new emails or emails on the server
• your local storage space is limited
• you are worried about backing up

If in doubt, go with IMAP. It’s the more modern protocol, it allows you to be flexible, your email is automatically backed up on the server, available server space usually isn’t an issue these days, and you can still store important emails locally.

What protocol did you choose and do you think you need to revise your decision?

Resources
Post Office Protocol – Wikipedia

Internet Message Access Protocol – Wikipedia

IMAP vs. POP – University of Minnesota