Soil-moisture probes, weather stations, valves and greenhouse controllers publish to one MQTT broker over LTE-M, NB-IoT or a LoRaWAN gateway. Your irrigation controller, farm dashboard and phone app subscribe, and valve commands still reach the field when the rural link drops for a while.
No card required
You build the applications, ConnectMQ moves the data. Probes, weather stations and valve controllers publish once over MQTT; the farm dashboard, irrigation controller, phone app and agronomy analytics you build each subscribe to the topics they need — add a new field or greenhouse without touching the others.
farm/field-7/soil-03/moisture
farm/field-7/valve-2/set
farm/field-7/valve-2/state (retained)A soil reading is only a few bytes. With MQTT the frame around it stays small too; with HTTPS, headers and handshakes make up most of what goes over the air. Fewer bytes means a smaller IoT data plan and less radio time on a battery-powered probe.
A common irrigation setup with MQTT: soil probes and valve controllers in the field publish over LTE-M, the irrigation controller in the farm office subscribes, and its commands travel back to the valves the same way.
05:45 Soil probe in field 7
Publishes soil moisture every 15 minutes over LTE-M. After a dry, windy night the reading at root depth falls to 18 %.
farm/field-7/soil-03/moisture → {"pct":18,"depth_cm":30}05:45 Irrigation controller
Subscribed to farm/field-7/+/moisture through ConnectMQ: below 22 % its rule schedules 40 minutes and sends the open command to valve 2 with QoS 1.
farm/field-7/valve-2/set → {"state":"open","minutes":40} · QoS 105:46 Valve controller 2
Opens the valve for 40 minutes — it closes on its own afterwards — and publishes its new state as a retained message, so every dashboard shows it at once.
farm/field-7/valve-2/state → {"state":"open","until":"06:26"} · retained05:46 Farmer
Gets a notification from the farm app, which subscribes to the valve state — no drive out to the field to check.
If the rural LTE-M link drops, the open command waits in the valve controller’s persistent session on ConnectMQ and is delivered with QoS 1 as soon as it reconnects (QoS 1 · persistent session).
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
Streetlights, parking, air and waste sensors
From first ESP32 to classroom labs
Start on the Free plan with no card. Basic covers up to 100 concurrent connections — enough for the probes, valves and weather station of a pilot field or greenhouse. Move to Scale when more fields, barns and cold stores come online.
