FluffyChat is an open-source chat client for the Matrix protocol, written in Flutter. The app is available for Android, iOS, the web, Linux, Windows and macOS. Users can hold private and group chats and use spaces, polls, custom stickers and group video calls. End-to-end encryption is enabled by default for private chats. Because FluffyChat is built on Matrix, it interoperates with other Matrix clients such as Element. It is only a client: you need a Matrix homeserver.
FluffyChat is developed under the AGPL-3.0 licence by Christian Kußowski (krille-chan), a volunteer project in Germany funded by donations. Where messages are stored is determined by the homeserver you choose, not by the app; an organisation can pick its own or a European-hosted server. According to its privacy policy, the app communicates only with that server and with OpenStreetMap for maps. Push notifications pass through Firebase Cloud Messaging and a FluffyChat gateway and contain only event identifiers. The default servers are chosen by the developers, who give no guarantee about their trustworthiness.