What is POP3?

POP3 is short for Post Office Protocol version 3. It is, along with IMAP4, the standard protocol for receiving e-mail from an e-mail server. Nearly every e-mail client supports POP3, and most e-mail providers offer POP3 by default.

Note that POP3 is not used for sending mail - it is usually paired with SMTP to send mail from the client's computer to the e-mail server.


POP3 is typically used to move e-mail from an e-mail server to the client's computer. Although many POP3 servers allow you to keep your mail on the server, POP3 operates under the principle that the server simply acts as a drop-box for your e-mail, and your client will maintain the authoritative collection of e-mail.

In general, when checking your mail with through POP3, your e-mail client connect to the server, check for new messages, and then move those messages to your computer, deleting the copy on the server.

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