IMAP

IMAP is a protocol used by email clients (like Outlook or Apple Mail,) to access and manage emails stored on a remote mail server. It allows users to read, organize, and delete email messages without downloading them permanently, keeping messages synced across multiple devices. 

Key features of IMAP: 

• Messages stay on the server and are accessed as needed 
• Actions like read, delete, or move are reflected across all devices 
• Often paired with SMTP (which sends the mail), while IMAP retrieves it 

IMAP also supports an optional extension called IDLE, which allows real-time message updates (aka push email). Most modern email clients use it to avoid constant refreshing. 

IMAP is used only on the receiving side of email – it plays no role in sending or delivery. Mailgun customers typically don’t use IMAP, since Mailgun handles email transmission and logging, not mailbox storage or client access.