Push-IMAP (P-IMAP or Push extensions for Internet Message Access Protocol) is based on IMAPv4 Rev1 (RFC 3501), but contains additional enhancements for optimization in a mobile setting. It was developed by Oracle and other partners, and submitted as input to Lemonade Profile IETF Working Group. Push IMAP was not included in the Lemonade Profile (RFC 4550).

The protocol was designed to provide for a secure way to automatically keep communicating new messages between a server and a mobile device like a PDA or Smartphone. It should reduce the time and effort needed to synchronize messages between the two (by using an open connection that is kept alive by some kind of heartbeat).

It will use as little bandwidth as possible, by using compression and command macros. P-IMAP features a mechanism for sending e-mail, derived from (but not identical to) SMTP, which lets clients offer a rich email service using a single connection.

It is sometimes incorrectly viewed as an alternative to the IMAP IDLE command (RFC 2177), but it is not. IDLE is one of the required mechanisms for a P-IMAP server to notify the client (optional notifications are SMS or WAP Push).

Whilst based on IMAP, Yahoo Mail and MobileMe for iPhone do not use a standard form of Push IMAP. Yahoo! Mail for iPhone uses a proprietary extension to the IMAP protocol. Apple Inc.'s MobileMe email for iPhone uses a server within Apple that maintains a persistent IP connection to each iPhone, which allows push email and soon background process updates.

See also

• IMAP
• Push e-mail
• Lemonade Profile
• SyncML

External links

• Internet Draft: P-IMAP
• Draft in IETF database
• Overview Presentation