Corporate messenger AtChat
AtChat is a corporate messenger that has all the necessary features for your business communication: personal and group chats, calls, file transfer, screen-sharing, and access management.
AtChat is a cross-platform application that can be installed on Windows, macOS, Linux, iOS, and Android. Additionally, AtChat is web-based and can run in Google Chrome, Mozilla Firefox, Safari, and Yandex Browser.
The server app can be installed in two ways: on-premise or cloud-based. The free plan allows you to use AtChat in a team of up to 20 members.