IMAPS

IMAPs refers to the Internet Message Access Protocol family used by email clients to access messages stored on a mail server. The core protocol is IMAP4rev1, standardized as RFC 3501, and it has many extensions that add capabilities such as server-side searching, multiple mailboxes, message flags, and stateful interaction. When people write IMAPS, they typically mean IMAP operating over TLS or SSL, which provides encrypted communication, usually on TCP port 993; standard IMAP often uses port 143 and can be secured with STARTTLS.

Key features of IMAPs include server-side storage of messages, support for multiple mailboxes, and the ability for clients to view, search, and manipulate messages without downloading them. Clients can fetch specific message data, apply and store flags (such as read or flagged), create and rename folders, and perform UID-based operations for reliable synchronization across devices. The IDLE command allows servers to push updates to clients, helping keep mailbox state in sync across concurrent accesses.

Security and deployment considerations commonly distinguish IMAP from IMAPS. While IMAP can operate in plain text, best practice is to use TLS or SSL to encrypt credentials and message data, either by connecting to IMAPS on port 993 or by upgrading a plain connection with STARTTLS. Weak or absent encryption can expose sensitive information, especially on public networks.

IMAPs is widely supported by major mail servers (such as Dovecot, Cyrus, Exchange) and client software, making it the preferred choice for users who access email from multiple devices or require robust server-side management of mail. It is often contrasted with POP3, which is designed for downloading mail to a single device.