Line is a freeware app for instant communications on electronic devices operated by LY Corporation. Line users exchange: texts, images, video and audio and conduct free VoIP conversations and video conferences. In addition, Line is a platform providing various services including: digital wallet as Line Pay, news stream as LINE Today, video on demand as Line TV and digital comic distribution as Line Manga and Line Webtoon.

Instant messaging (IM) technology is a type of online chat allowing immediate transmission of messages over the Internet or another computer network. Messages are typically transmitted between two or more parties, when each user inputs text and triggers a transmission to the recipient(s), who are all connected on a common network. It differs from email in that conversations over instant messaging happen in real-time. Most modern IM applications use push technology and also add other features such as emojis, file transfer, chatbots, voice over IP, or video chat capabilities.