Mumble

Mumble is an open-source, low-latency, high-quality voice chat software. There are two modules in Mumble; the client (mumble) and the server (murmur). The client works on Windows, Linux, FreeBSD, OpenBSD, and macOS, while the server should work on anything Qt can be installed on. Low-latency and high-quality voice-chat program written on top of Qt and Opus. Administrators appreciate Mumble for being able to self-host and have control over data security and privacy. Some make use of the extensive permission system for complex scenarios (for example separating two groups but leaders being able to talk to both). Some love to provide their users with additional functionality with scripts making use of server APIs, or host music bots and the like that connect to the server. Those that have an existing user database often make use of authenticators to allow authenticating with existing account login data.