In email technology, IDLE is an IMAP feature described in RFC 2177 that allows a client to indicate to the server that it is ready to accept real-time notifications.
The IDLE feature allows IMAP email users to immediately receive any mailbox changes without having to undertake any action such as clicking on a refresh button, or having the email client automatically and repeatedly ask the server for new messages.
IMAP4 servers that support IDLE will include the programming string "IDLE" in the result of their CAPABILITY command. This allows email users to receive near instant notification of a new email.
Client software with support for IMAP IDLEAirmail for OS XApple Mail, IDLE command introduced with version 3.Becky!, IDLE command introduced with version 2.56 (2010/09/29).ConeCouriereM ClientEmailPush for iPhoneEmansio For Windows MobileEvolution (IMAPX introduced as "IMAP+" in version 2.30)FlexMail For Windows MobileibisMail for iPhonei.Scribe / InScribeK-9 Mail for AndroidKaiten Mail for AndroidKmail as with KDE SC 4.7MailbirdMail application on Nokia N9MetroMail for Windows Phone 8Microsoft EntourageMicrosoft OutlookMicrosoft Outlook ExpressMicrosoft Windows MailMicrosoft Windows Mail App for Windows 8Mozilla Thunderbird/SeaMonkeyMuttOpera MailPeek (mobile email device)ProfiMail For Windows Mobile and SymbianSchedHandler For Windows MobileSparrow for OS XSymbian smartphonesTiverias GPush for iPhoneTreo smartphonesThe BatTrojitáwebOS smartphonesZimbra Desktop for Windows, Linux & MACServer software with support for IMAP IDLEacIMAPArchiveopteryxCommuniGate ProContactOfficeCourier Mail ServerCyrus IMAP serverDavmail GatewayDBMail IMAP and POP3 serverdovecot IMAP serverEudora Internet Mail ServerhMailServerIceWarp Mail Serverisode M-Box POP/IMAP GatewayKerio Connect (formerly Kerio MailServerKolab Groupware ServerLumiSoft Mail ServerMailEnableMailSiteMailtraqMDaemon Mail ServerMercury 32Microsoft Exchange ServerPanda IMAPSmarterMail 8.xSun Java System Messaging ServerSynchronica Mobile GatewayTeamware OfficeUW IMAPwodImapServer ActiveX componentZarafa Collaboration PlatformZimbra Collaboration ServerZoho MailServices that support IMAP IDLEFastMail