Real-time IoT and messaging features fall apart without a reliable message broker behind them. For this build I deployed and configured Mosquitto, the lightweight MQTT broker, on an AWS EC2 Ubuntu server — the backbone for publish/subscribe communication between devices and services.
The approach: provision the EC2 instance, install and harden Mosquitto, configure the listener and authentication, then prove it actually works end to end with live publish/subscribe message tests across topics. That verification step matters — a broker that "starts" is not the same as a broker that reliably delivers messages under real conditions.
The result is a working, tested MQTT backbone suitable for IoT telemetry, device control, and real-time messaging apps. It is the same pattern I use when wiring event-driven and IoT systems on AWS.