ChatApps

Chatapps are software applications that enable direct and group messaging between users over the internet. They are typically designed for mobile devices but are also available as desktop or web clients and can synchronize messages across multiple devices.

Core features commonly include text messaging, voice and video calls, file sharing, voice messages, and group chats. Many chatapps support presence indicators, message read receipts, and status updates. Privacy features vary; several apps offer end-to-end encryption for messages, while others encrypt only in transit or store messages on servers for syncing, indexing, or backup.

Architecture and operation: Most chatapps use a client–server model with servers operated by the service provider. Messages pass from the sender's device to the server and then to recipients, with real-time delivery facilitated by protocols such as WebSocket or MQTT. Push notifications are used to alert users when they are offline.

History and impact: Modern chatapps evolved from the late 2000s with mobile-first messaging and have expanded into business use, customer support, and platform ecosystems through APIs and bots. They affect communication habits, social interaction, and privacy debates, and are subject to regulatory and security considerations, including data retention and surveillance concerns. Notable examples include WhatsApp, Facebook Messenger, WeChat, Telegram, and Signal.