Email Hosting: POP3 vs. IMAP

11008394895_5e22c3af3c_bWhat is the difference between POP3 and IMAP? Both are standard email protocols for accessing your email through a remote server, such as an iPad or smartphone. Both can deliver your email to you no matter where you are, but both function in two different ways. Many email hosting companies now use IMAP, even though that POP3 has some advantages. Read more to find out why.


POP (Post Office Protocol) is an old but reliable method of delivering emails from your server all at one time. It is still the most common email protocol method and is very basic, but limited. This limited functionality is also why Centennial Arts uses IMAP, one of the best protocols for current Email Hosting services.

All you have to do is connect to your email server on the Internet, download a copy of your awaiting messages via POP, and then disconnect. POP3 lets you download messages from the server, and optionally delete them as they’re downloading. Older versions of POP automatically deletes any mail from the server once it has been received by you on your device, therefore there is no two-way synchronization between your device and the server.1

Although POP deletes your messages from the server, you can decide to leave a copy of the message on the server to be downloaded again later if necessary by another device or program. Traditionally, this is how most personal email hosting systemswere set up. Now, as mobile technology grows more ubiquitous, more and more users are seeking to permanently store and access their email online. This is where IMAP comes into play.

Advantages of POP3:

  • A local copy of your email.
  • Very little remote server storage space overhead required (if emails are deleted from the server as they are retrieved).
  • Consolidation of many email accounts and servers to deliver to one inbox.

Disadvantages of POP3:

  • No remote copy (if emails are deleted from the server as they are retrieved).
  • No remote web access or synchronization between several programs or devices.
  • All mail is stored in one (and only one) place.
  • Local copies of messages still requires disk space to store messages.
  • Local copies of messages are vulnerable to data loss or security threats.
  • Not a performance oriented protocol for email hosting.



IMAP (Internet Message Access Protocol) is a two-way email management protocol with a sophisticated but user friendly interface for sharing, organizing, and enabling flexible access to multiple users.

Any change you make in any IMAP client will automatically synchronize with the server. This means any email read on your device will also automatically appear read when you check your account later via webmail or your desktop computer. Any messages or folders you read, move, or delete will be updated across all devices. No matter which client you use, you will see the same inbox, with the same settings.2

IMAP is currently used on newer smartphones. IMAP also supports offline use, so any changes made without an Internet connection will be updated when you connect to the server again. All messages are permanently stored on the server until purposely deleted. This protocol is fantastic for email hosting due to its synchronous nature, keeping your inbox up-to-date whenever you need it.


  • You can keep a local archive, as well as rest assured knowing a copy is stored on the mail server.
  • With a persistent Internet connection, only email headers are downloaded, so you can see your mail faster. The full message is only downloaded when you request to read it.
  • Size of your message archive is limited only by your account’s server space, not your personal device(s).


POP only downloads messages to an email client and is less convenient. IMAP lets you manipulate stuff on the mail server like creating folders, etc. IMAP is easy and automatically syncs all email clients with the email hosting server.

There’s not a noticeable difference between the two, even though they function differently. Most mail servers support POP3, but not all support IMAP. On the contrary, you could have one computer set to access an account with POP3 and another set to access the same account with IMAP. There’s no difference in the actual mail stores on the server; they’re just two different methods of accessing the same information.




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