Internet Message Access Protocol (IMAP)

Internet standard. The communication rules that systems follow to let you read and retrieve email messages from your inbox provider. RFC 9051 defines this version 4rev2 of the standard.

To access email from any location or device, you use the Internet Message Access Protocol (IMAP). IMAP doesn't download the message before letting you read it. You can read the message and choose to download it. It doesn't download attachments until you click on them. Inbox providers use this protocol more than its predecessor, the Post Office Protocol (POP). POP contacted the provider, downloaded the messages, then let you read them.

Email services like Microsoft Outlook and Gmail use this protocol.