Facebook has released an experimental messaging app for Apple Watch called Kit (or Keep in Touch). It appears to work in a similar way to iMessage on the device, as you can share emoji, voice messages, your location, doodles and dictated messages over Messenger with a tap.
The app, which TechCrunch spotted, can also read incoming messages. Facebook's Messenger already works on Apple Watch, but Kit is primarily designed to help folks stay in touch with close friends and family. It has a Watch-friendly interface and you won't need to pick up your phone to respond to loved ones with a quick emoji or voice message. It could also prove a useful way for you to keep in touch with people who don't have access to iMessage.