IMAP

Internet Message Access Protocol

A widely used email protocol that enables users to access and manage their messages directly on a mail server rather than downloading them permanently to a single device. This server-centric design ensures that email data remains consistent and synchronized across multiple devices—desktops, laptops, smartphones, and tablets.

When a user performs an action such as reading, flagging, moving, or deleting a message, IMAP updates the server, and those changes are instantly reflected in all connected clients. This makes it ideal for modern email workflows where messages must remain accessible and consistent from anywhere.

IMAP typically uses TCP port 143 for unencrypted communication, but most modern email providers require secure connections via SSL/TLS over port 993. Secure IMAP (IMAPS) encrypts the transmission of email data, protecting credentials and content from interception.

In contrast to POP3, which downloads emails and often removes them from the server, IMAP maintains all mail—including folder structures—on the server. This enables advanced organization, easier backups, and seamless integration with cloud-based email systems. Because of its flexibility and synchronization capabilities, IMAP has become the default choice for both personal and enterprise email services.