Streetlights, parking sensors, air-quality stations and waste bins come from different vendors and report over different networks. Publish them all to one MQTT broker, in one topic tree, and let every city system subscribe to what it needs.
No card required
You build the applications, ConnectMQ moves the data. Lamp controllers, sensor gateways and LoRaWAN network servers publish once; the operations dashboard, citizen app, maintenance system and open-data portal each subscribe to the topics they are allowed to see — add a new vendor or a new consumer without rewiring the others.
city/downtown/congress-ave/lights/light-118/state (retained)
city/downtown/congress-ave/lights/light-117/set
city/downtown/congress-ave/parking/zone-4/occupancy (retained)Congress Avenue dashboard subscribes to city/downtown/congress-ave/#
matched by the subscription
Name topics after where things are — city, district, area, asset — and every system finds data by location, whichever vendor installed the sensor. One wildcard subscription gives a district dashboard everything on Congress Avenue, and ACLs keep each department and vendor to its own branch.
A typical city setup with MQTT: lamp controllers on the poles publish their state over LTE-M, the city operations platform subscribes to the district’s branch of the topic tree, and the same broker carries its commands back to the lights. Poles and office both connect out to ConnectMQ over TLS.
23:41 Lamp controller on light-118
Detects that the LED driver has failed and publishes the lamp’s new state as a retained message.
city/downtown/congress-ave/lights/light-118/state → {"lamp":"fault","code":"DRIVER"}23:41 City operations platform
Subscribed to city/downtown/congress-ave/# through ConnectMQ: it opens maintenance job #2207 and raises light-117 and light-119 from 40 % to 100 %.
city/downtown/congress-ave/lights/light-117/set → {"dim":100}23:41 Neighbouring lights
Both controllers switch to full brightness and confirm with their new state, so the dark gap on the pavement is covered.
city/downtown/congress-ave/lights/light-117/state → {"lamp":"on","dim":100}23:42 Maintenance crew’s app
Gets the job with the pole number and fault code. Once light-118 reports “on” again, the platform dims its neighbours back to 40 %.
If a lamp controller loses power or signal, the broker publishes its retained Last Will city/downtown/congress-ave/lights/light-118/status → offline — the dashboard shows the light as unreachable instead of its last good state.
Machines, PLC gateways, OEE and quality data
Hubs, sensors and Home Assistant setups
Vehicle tracking, telematics and cold chain
Meters, EV chargers, solar and batteries
Smart devices you ship to your own customers
Robot fleets talking to fleet managers and AI pipelines
Power, cooling and rack environment
Soil probes, weather stations and irrigation
From first ESP32 to classroom labs
Start on the Free plan with no card. Basic covers up to 100 concurrent connections — enough for the lamp controllers of a pilot street and the network servers that bring in your LoRaWAN sensors. Move to Scale when more districts go live.
