IMAP or POP?

There are two common protocols for collecting email from a mail server.

POP3 downloads the email from the server to your local device and then deletes the data from the server. (This can usually be configured at your device end to not delete, or delete after so many days.)

IMAP stores the data on the remote server which allows it to be synchronised across multiple devices. It only gets deleted from the server when you delete the email, or archive it down on your local device.

Common jargon:

  • "email server" - that is the internet computer which processes your email
  • "email client" - this is the software on your local device(s) that download the emails for you to read and reply to. Outlook is the most common on Windows, Mail on Mac. Others include Thunderbird and eM Client.
  • "webmail" - this is a website location to read into your email server direct using any internet browser (like Chrome, Edge, Safari etc)

Here are the differences summarised:

IMAP POP3
IMAP only downloads a copy of the files from the server to the local device. Emails stay on the server. POP3 downloads the emails from the server to save on the local device, and deletes the data from the server.
You can view the same email on multiple local devices. You can view the email only on one device (there are tricks around this, but gets messy).
Sent emails are saved back to the server - you can see see these on multiple local devices. Sent emails are only available on the one device that sent the email. You won't see them elsewhere, even through Webmail (unless you sent from Webmail, in which case you won't see them on any device!)
You can use folders to organise emails on the server using IMAP. POP3 only allows you to add to local folders in your email client and is not saved back to server.
IMAP takes up a larger server space to store your emails. POP3 doesn't require high server space.
IMAP relies on server backups which may cost to retrieve via system admin. Regular archiving to your own backup is advisable.  POP3 relies on you backing up your own email on your own device (which you should be doing anyway).

Which protocol should you choose?

Both POP3 and IMAP have pros and cons.

Choose POP3 if

  • You work on a single dedicated device and use one email client only.
  • You receive a large number of emails and have limited storage space on the email server.
  • You have an unreliable network connection and often work offline.

Choose IMAP if

  • You work from multiple devices and need to use different email clients.
  • You want to synchronize the data over all the devices to access anywhere.
  • Server Storage space is not a problem.

For POP3 set up see this page.

For IMAP set up see this page.