iMessage is an instant messaging service developed by Apple Inc. and launched in 2011. iMessage functions exclusively on Apple platforms: macOS, iOS, iPadOS, and watchOS.
Core features of iMessage, available on all supported platforms, include sending text messages, images, videos, and documents; getting delivery and read statuses (read receipts); and end-to-end encryption so only the sender and recipient can read the messages, and no one else, including Apple itself, can read them. The service also allows sending location data and stickers. On iOS and iPadOS, third-party developers can extend iMessage capabilities with custom extensions, an example being quick sharing of recently played songs.
Launched on iOS in 2011, iMessage arrived on macOS (then called OS X) in 2012. In 2020, Apple announced an entirely redesigned version of the macOS Messages app which adds some of the features previously unavailable on the Mac, including location sharing and message effects.
iMessage was announced by Scott Forstall at the WWDC 2011 keynote on June 6, 2011. A version of the Messages app for iOS with support for iMessage was included in the iOS 5 update on October 12, 2011. On February 16, 2012, Apple announced that a new Messages app replacing iChat would be part of OS X Mountain Lion. Mountain Lion was released on July 25, 2012.
On October 23, 2012, Apple CEO, Tim Cook announced that Apple device users have sent 300 billion messages using iMessage and that Apple delivers an average of 28,000 messages per second. In February 2016, Eddy Cue announced that the number of iMessages sent per second had grown to 200,000.
In May 2014, a lawsuit was filed against Apple over an issue where, if a user switched from an Apple device to a non-Apple device, messages being delivered to them through iMessage would not reach their destination. In November 2014 Apple addressed this problem by providing instructions and an online tool to deregister iMessage. A federal court dismissed the suit in Apple's favor.