Differences Between IMAP & POP3 Protocol



We routinely recommend that email users switch to using the IMAP protocol with their email connection methods, as the IMAP protocol provides unique benefits to email utility that POP3 lacks. These benefits can make personal workflow a much more seamless process in our always-online work culture.


Key Benefits

  • Mail is stored on a remote server.
  • Faster overview as only headers are downloaded unless the content is explicitly requested.
  • Saves local storage space.

The primary differences between the two protocols is that the IMAP protocol will sync with a source server across all devices that connect to a specific user. This means that using a number of devices like a work computer, home computer, and smartphone, that are all connected to the same user, are able to present the same content. This has the benefit of keeping the mail directory management time down as each device will correlate to the source server.

During the IMAP connection, the protocol will connect to the remote server initially and fetch the user requested content. It will then cache the content locally. Content like new mail, message summaries, and content of explicitly selected emails. After the user content is fetched, the next step is to process the user edits like marking messages as read, moving, or removing messages from the inbox. Once this back and forth is complete your IMAP device will disconnect from the remote server.


Key Benefits

  • Mail is stored locally.
  • Connection is only necessary for sending and receiving mail.
  • Saves space on the server.

The POP3 protocol is engineered from the perspective that only the email client requires access to mail on the server and that the messages are best stored on the requesting client. While this can have benefits in very unique situations for email users. This ideology of email management can be rather burdensome as there is not a centralized method of control for the individual email client devices.

During the POP3 connection, the email client device will connect to a remote server to download all available mail. It will then store the mail locally on the email client device that made the retrieval. When the email client device connects will attempt to remove the messages from the server by default; however, there are generally options to leave a copy of the message on the remote server instead of deleting the message. After the retrieval, the device will disconnect from the remote server.

Why To Switch To IMAP

The main reason that we are often recommending that our email users switch to using the IMAP protocol for email client device connections is that there is a routine submission of tickets regarding lost emails. Generally, the culprit is POP3 downloading the messages to a new device or rarely used device and our client was unaware that the messages had been downloaded.

When that happens it can cause a lot of confusion. Having the POP device configured to leave a copy of the messages on the remote server can help to alleviate that issue, but in the long run, switching the email client device to use an IMAP protocol connection can keep all connecting devices on the same page by synchronizing with the remote server instead of pulling the messages and deleting them.