Eclipse Mosquitto

Eclipse Mosquitto is an open-source MQTT message broker from the Eclipse ecosystem. It implements MQTT versions 5.0, 3.1.1, and 3.1 for lightweight publish-and-subscribe communication. The project is designed for IoT, machine-to-machine messaging, telemetry, home automation, embedded devices, and distributed systems that need efficient event delivery. It includes the broker itself, C and C++ client libraries, and command-line tools for publishing, subscribing, request-response testing, password management, broker control, and signaling. Mosquitto is portable and can run on small devices, servers, containers, and many operating systems. Its main value is providing a mature, lightweight, widely adopted MQTT implementation for reliable messaging in constrained and production environments.