MQTT
The lightweight publish/subscribe protocol that moves device telemetry — the lingua franca of medical IoT.
In one line
MQTT (Message Queuing Telemetry Transport) is a tiny publish/subscribe messaging protocol designed for unreliable networks and constrained devices — which is why most connected medical devices and remote-monitoring kits speak it.
How it works
Devices don't talk to each other directly. Each client connects to a central
broker (Mosquitto, EMQX, HiveMQ…) and either publishes messages to a named
topic (ward3/bed12/spo2) or subscribes to topic patterns (ward3/+/spo2).
The broker routes messages from publishers to subscribers. Three QoS levels trade
delivery guarantees against overhead (0 = at most once, 1 = at least once, 2 = exactly
once), a retained message gives new subscribers the last known value instantly, and
the Last Will & Testament lets the broker announce a device that vanished — how a
monitoring dashboard knows a sensor went offline rather than "everything is fine".
Where it shows up in digital health
Remote patient monitoring kits publish vitals over MQTT (often via a home gateway); hospital IoMT platforms ingest device streams through brokers before converting them to FHIR Observations; mannequin/simulation bridges stream synthetic vitals the same way. In this platform's future IoT lab, the device → broker → FHIR pipeline is exactly what you'll build — with synthetic patients on the other end.