Differences between IMAP and POP3

Both IMAP and POP3 are two configuration protocols for email accounts, which represent the two most used email reception protocols, since they support most email servers and client programs such as Outlook Express or Mozilla Thunderbird .

Despite having specific characteristics, both protocols are often confused due to the lack of information about them. That is why, in this article, we present the differences that exist between both protocols based on their specifications.


It can be said that IMAP stands for Internet Message Access Protocol (Internet Message Access Protocol). This is an application protocol that allows users to access messages stored on an Internet server.

Through IMAP you can access email from any device with an internet connection. This is a new protocol that allows many functionalities, among them the most important is that it allows messages to be viewed remotely and not downloading the messages as other protocols do.

On the other hand, IMAP has different versions: IMAP 2, IMAP 3, IMAP 2 bis and IMAP 4. All of them introduced different tagging commands and responses, as well as innovating by allowing messages to be created, deleted and saved as drafts in the respective mailboxes. Some of the advantages of IMAP include:

  • With IMAP you can connect more than one user to the same account.
  • It works in permanent connection mode, so it notifies immediately of the arrival of new mail.
  • The download of the message occurs only when the user wants to read it.
  • Local storage of the message is optional (an option of the mail client).
  • It allows the search of messages by means of keywords.
  • Shared folders can be created with other users depending on the server.
  • The storage of messages and folders on the server allows their use from multiple devices and simultaneously.


POP stands for Post Office Protocol (Post Office Protocol), this protocol is used to obtain email messages stored on a remote server. POP3 is designed to allow users with intermittent or very slow connections to download their email while online and check it later, even when disconnected from the Internet.

The main feature of POP3 is that when you check email over a POP3 connection, new messages are downloaded to your computer and deleted from the server. Another advantage of POP3 is that emails appear immediately because they remain resident on the device once downloaded. However, this protocol has the disadvantage that by default it deletes the messages from the server, making it impossible to access them from another device.

Taking these characteristics into consideration, the main differences between IMAP and POP3 are presented:

It allows the viewing of emails that are on the server, instead of downloading them. It downloads the emails that are in the inbox and stores them locally on the computer.
Received messages are downloaded but a copy is left on the server. The messages are downloaded to the client or program used to be able to read them without an internet connection.
With IMAP, more than one user can connect to the same account. With POP3, only one user can connect to download email.
Not all mail clients and services support it. It is supported by all mail clients and services.

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