What is the difference between POP3 and IMAP?

When you have a Business Essential, Business Pro, or Premium Mailbox, you can access your email using POP3 or IMAP. These are two different protocols used by email applications to access messages stored on the email server.

POP3

POP3 (Post Office Protocol 3) is primarily designed to download email from the server to an email client, such as a desktop or mobile application.

Depending on your email client’s settings, messages downloaded using POP3 may be removed from the email server after they are downloaded. Most email clients can also be configured to leave a copy of downloaded messages on the server.

Because POP3 is primarily designed for downloading messages, it does not have the same level of synchronisation between devices as IMAP. For example, folders and the read/unread status of messages may not be synchronised between your email client and webmail.

If you use POP3 and leave messages on the server, those messages will continue to count towards your mailbox storage limit.

IMAP

IMAP (Internet Message Access Protocol) keeps your email stored on the email server and synchronises your mailbox with your email client.

This means that changes made in one email client are generally reflected across other devices and webmail. For example:

• Messages marked as Read on one device will appear as read on other devices.
• Folders created in your email client are available through Webmail and other IMAP-connected devices.
• Messages moved between folders are synchronised across your devices.
• Sent messages and other mailbox folders can be accessed from multiple devices.

Because messages remain on the mail server, they count towards your mailbox storage limit.

You should regularly monitor your mailbox usage and remove unnecessary messages if you are approaching your storage limit.

Which should I use?

IMAP is recommended if you access your email from multiple devices, such as a computer, phone, tablet, or webmail. It keeps your mailbox synchronised across your devices and provides a consistent view of your email.

POP3 may be suitable if you primarily use a single email client and want to store your messages locally. If you use POP3, make sure your email client is configured appropriately for whether you want messages to remain on the mail server.

For most users, IMAP is the recommended choice.