Device communication
MQTT Communication for Telemetry, Events and Device Integration
MQTT-based communication for device telemetry, asynchronous events, diagnostics and integration of embedded devices with service, monitoring and automation systems.
MQTT is useful when device information should be distributed asynchronously: status changes, telemetry, alarms, events, diagnostic data or integration messages. It helps decouple producers and consumers of device information and avoids forcing all communication into synchronous request/response APIs.
Where MQTT fits
Telemetry
Publish device values, counters, measurements, subsystem states and runtime information.
Events and alarms
Distribute state changes, warnings, errors and service-relevant events to UI, monitoring or backend systems.
Integration
Connect device platforms to local services, test environments, gateways, cloud connectors or customer monitoring systems.
Typical use cases
- Device status publishing
- Telemetry and measurement data forwarding
- Alarm and event distribution
- Service and diagnostic event streams
- Communication between device services and browser-based UI
- Integration with monitoring, test bench or automation environments
- Store-and-forward concepts for intermittent connectivity
- Gateway or cloud connector integration
REST vs MQTT
REST and MQTT should not be treated as competing technologies. They solve different communication problems and often work best together in a device architecture.
| Communication need | Typical choice |
|---|---|
| Read configuration or trigger a controlled operation | REST API |
| Publish status changes, telemetry or alarms | MQTT |
| Integrate browser UI with structured service functions | REST plus MQTT events |
| Support monitoring, service or cloud ingestion | MQTT with defined message contracts |
Architecture pattern
- Device data source: embedded software, C/C++ services, drivers or hardware communication layers provide device information.
- Message preparation: a service layer validates, normalizes and publishes data with defined topic and payload structure.
- MQTT broker: the broker routes messages between device services, UI, monitoring systems, gateways or cloud connectors.
- Consumers: browser UI, diagnostics tools, automation systems, gateways or cloud connectors consume messages through documented contracts.
Topic and message design
The main engineering value is not simply adding MQTT to a device. The important part is designing topic structure, message contracts and diagnostic behaviour so that the communication remains understandable and maintainable over time.
Topic structure
- Device identity and product line
- Subsystem or module naming
- Status, telemetry and event separation
- Service and diagnostics topics
- Versioning and compatibility considerations
Payload structure
- Stable message schema
- Timestamp and source information
- Device state and error context
- Units and value semantics
- Clear handling of optional fields
Typical design topics
- Topic structure and naming
- Message schema and payload format
- Status, telemetry and event separation
- Retained messages and last-known state
- Quality of Service strategy
- Connection and reconnection behaviour
- Diagnostics for message flow and broker connectivity
- Security and access control
- Documentation for service and integration teams
Device diagnostics through MQTT
MQTT can be useful for diagnostic visibility. Device services can publish communication status, subsystem readiness, warning states, error events and version information. This makes it easier to understand field behaviour, service issues and integration problems without direct access to internal device tools.
| Diagnostic area | Example MQTT content |
|---|---|
| Device health | Ready state, subsystem status, warning flags and error state. |
| Communication | Connection state, broker status, message counters and reconnect events. |
| Service | Maintenance events, configuration changes, calibration state and service actions. |
| Release and versioning | Firmware, service layer, UI and configuration versions visible for support workflows. |
Security considerations
- MQTT access should be controlled according to the device environment and threat model.
- For remote or customer-facing communication, authentication and encryption must be considered from the beginning.
- Topics should not expose unnecessary internal implementation details.
- Command topics, if used, require strict validation and state handling.
- Service and diagnostic information should be separated from normal operational data where useful.
Deliverables
- MQTT topic concept
- Payload schema and event model
- Service layer integration
- Diagnostics and logging concept
- Security and connection handling concept
- Documentation for internal and external integration
- Test approach for message behaviour
Use MQTT where event-driven device communication makes sense
I help define and implement MQTT-based communication paths for embedded devices, service interfaces, diagnostics and external integration.