Infrastructure
What is IMAP (Internet Message Access Protocol)?
A protocol for reading and managing email on a remote mail server while messages stay stored server-side.
IMAP lets an email client read, organize, and sync messages that remain on the mail server, so the same mailbox state (folders, read/unread flags) appears consistently across multiple devices. It typically runs over port 993 with implicit TLS, or port 143 with STARTTLS. Unlike POP3, IMAP does not download-and-delete by default; it leaves mail on the server and synchronizes changes bidirectionally.
Why it matters for cold email
Cold-email tools connect to inboxes over IMAP to sync replies, detect bounces, and power a unified inbox, so a broken or rate-limited IMAP connection means responses and auto-replies go undetected. That skews reply-rate metrics and lets sequences keep emailing people who already replied, which damages sender reputation.
Related terms
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