IMAP vs POP3

Both IMAP and POP3 are popular protocols for transferring e-mail. Each has unique advantages and disadvantages. Here is a summary of the advantages and disadvantages of each.

POP3

POP stands for “Post Office Protocol 3”. Each time you check your mail, POP3 sends all incoming messages to your local application. Once your computer confirms to the server that the messages were transfered correctly, the messages are automatically deleted from the server. 

When a POP3 server receives your request for e-mail, it sends the entire contents of each message to your e-mail program. Once you receive the email, the message is no longer stored on the server unless you specifically tell it to keep a copy.

IMAP

IMAP stands for “Internet Message Access Protocol”. It also allows you to download e-mail from the server, but it sends only a short 'header' containing the message's meta-information (Title, From Address, etc.). Sending only the header can save significant time if message are long or contain large embedded files. With IMAP, the server is typically configured to keep the e-mail, and sends you a new copy each time you view a message.

IMAP servers can also be configured to send the complete messages to your local machine. When this is done a sophisticated sychronlization process keeps the two sets of messages in sync. For example, if you delete a message in one place it will automatically be deleted on another machine the next time they connect.

POP3

IMAP

Relatively easy to setup and use.

Strong redundancy.

Messages are stored on your local computer, and are available even without Internet access.

Messages are stored on the remote server, where they are available from any device with an Internet connection.

If you lose the messages stored on your local computer you can not recover it from the server.

If you lose access to the Internet, you will not be able to read your email.