Email relies on several protocols to send, receive, and store messages. The most important are:

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SMTP

Simple Mail Transfer Protocol (SMTP) is used to send emails from a client to a server or between servers.

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POP3

Post Office Protocol 3 (POP3) allows users to download emails from the server to their local device and then delete them from the server.

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IMAP

Internet Message Access Protocol (IMAP) lets users view and organize emails on the server, syncing across multiple devices.
Want to dive deeper? Read our guide on How Email Works!