Differences between POP3 and IMAP

POP3 (Post Office Protocol 3) and IMAP (Internet Message Access Protocol) both are MAA (Message accessing agent), both of these protocols are used to the retrieve message from the mail server to the receivers system. Both of these protocols are accounted for spam and virus filters. IMAP is more flexible and complex than POP3.

POST OFFICE PROTOCOL (POP3)INTERNET MESSAGE ACCESS PROTOCOL (IMAP)
POP is a simple protocol that only allows downloading messages from your Inbox to your local computer.IMAP is much more advanced and allows you the user to see all the folders on the mail server.
The POP server listens on port 110, and the POP with SSL secure(POP3DS) server listens on port 995he IMAP server listens on port 143, and the IMAP with SSL secure(IMAPDS) server listens on port 993.
In POP3 the mail can only be accessed from a single device at a time.Messages can be accessed across multiple devices
To read the mail it has to be downloaded on the local system.The mail content can be read partially before downloading.
The user can not organize mails in the mailbox of the mail server.The user can organize the emails directly on the mail server.
The user can not create, delete or rename email on the mail server.The user can create, delete or rename email on the mail server.
A user can not search the content of mail before downloading to the local system.A user can search the content of mail for specific string before downloading.
After download, the message exists in the local system if the local system crashes message is lost.Multiple redundant copies of the message are kept at the mail server, in case of loss of message of a local server, the mail can still be retrieved
Changes in the mail can be done using local email software.Changes made web interface or email software stay in sync with the server.
All the message are downloaded at once.Message header can be viewed prior to downloading.