I featured this service a year back when it was still called Ring but it has rebranded now. Jami is Free Software. Secure, distributed, adaptable, powerful, free with no ads, Jami aims to give back its users their freedom. It is peer-to-peer like the original Skype was, which means your messaging and audio/video is direct and not via a centrally hosted server.
The application uses distributed hash tables (DHT) to establish communications. This technology eliminates the use of centralized registers (servers) and the retention of personal data. Jami is based on distributed network technology, eliminating the need for servers. Mass surveillance can not be undertaken by the servers as there is not any.
Jami stores your secrets (private keys for encryption and identity) only on the device which executes it, which belongs to you. Your device is, therefore, the sole holder of your information.
Jami has a multitude of uses. Whether sending text messages, making secure, reliable audio and video calls, or sharing files, Jami provides high-quality communication and data exchange.
Whether interacting with your family on the other side of the world or sharing documents securely with your colleagues, Jami offers a complete range of possibilities for your communication needs.
See https://jami.net/ Jami
Jami - the distributed and open source communication platform Jami