Facebook Messenger (commonly known as Messenger) is an American messaging app and platform developed by Facebook, Inc. Originally developed as Facebook Chat in 2008, the company revamped its messaging service in 2010, and subsequently released standalone iOS and Android apps in August 2011 and standalone Facebook Portal hardware for Messenger-based calling in Q4 2018. Later on, Facebook has launched a dedicated website interface (Messenger.com), and separated the messaging functionality from the main Facebook app, allowing users to use the web interface or download one of the standalone apps. 2020年4月，Facebook正式發布了Messenger for Desktop，該Messenger在Windows 10和MacOS上得到了支持，分別在Microsoft Store和App Store上分發。
用戶可以發送消息並交換照片，視頻，貼紙，音頻和文件，以及對其他用戶的消息做出反應並與機器人進行交互。該服務還支持語音和視頻通話。獨立應用程序使用多個帳戶支持，可選的端到端加密對話以及玩遊戲。
