Topic structure

Topics are generated from a configurable template. The default template is:

${account_id}/${location_id}/${serial_number}/${message_type}

Template variables

Variable	Description	Example Value
`${account_id}`	Account ID	`e70436c6-877c-11e9-b532-0a0fcefe620c`
`${location_id}`	Location ID within the organization	`8ef8f04a-686f-473e-b122-c2c52ea085eb`
`${serial_number}`	Device serial number	`2930123456`
`${message_type}`	`sample` for sensor data, `metadata` for hub status	`sample`

Template rules

Maximum 512 characters
Allowed characters: alphanumeric, -, _, /, and template variables
No spaces or special characters outside the allowed set
Unrecognized ${...} variables are rejected

Custom topic examples

airthings/${account_id}/devices/${serial_number}/${message_type}

iot/building/${location_id}/${serial_number}/data

${account_id}/${message_type}/${serial_number}

Sample Feed payload

Published when sensor readings are received from a device. The ${message_type} resolves to sample. Each device sample is published as an individual MQTT message.

{
  "serialNumber": "2930123456",
  "recorded": "2026-03-23T12:30:45Z",
  "rssi": -65,
  "batteryPercentage": 87,
  "temp": 22.5,
  "humidity": 45.2,
  "co2": 420,
  "tvoc": 150,
  "pressure": 1013.25,
  "pressureDifference": 0.5,
  "radonShortTermAvg": 48.0,
  "pm1": 2.5,
  "pm25": 5.5,
  "light": 75.0,
  "lux": 500,
  "soundLevelA": 42,
  "sensorUnits": {
    "temp": "c",
    "pressure": "hpa",
    "radon": "bq",
    "voc": "ppb"
  },
  "ratings": {
    "temp": "GOOD",
    "humidity": "GOOD",
    "co2": "POOR"
  },
  "deviceName": "Conference Room Sensor",
  "locationName": "Oslo Location"
}

Field reference

Field	Type	Description	Unit
`serialNumber`	string	Device serial number	—
`recorded`	ISO 8601	Timestamp of reading	—
`temp`	float	Temperature	°C or °F (per config)
`humidity`	float	Relative humidity	%
`co2`	float	Carbon dioxide	ppm
`tvoc`	float	Total VOCs	ppb or µg/m³ (per config)
`pressure`	float	Barometric pressure	hPa or inHg (per config)
`radonShortTermAvg`	float	Short-term radon average	Bq/m³ or pCi/L (per config)
`pm1`	float	Particulate matter less than 1 µm	µg/m³
`pm25`	float	Particulate matter less than 2.5 µm	µg/m³
`light`	float	Ambient light	%
`lux`	float	Illuminance	lux
`soundLevelA`	float	A-weighted sound level	dBA
`rssi`	int	Radio signal strength	dBm
`batteryPercentage`	int	Battery level	%
`pressureDifference`	float	Pressure difference	Pa
`sensorUnits`	object	Units used for each sensor in this payload	—
`ratings`	object	Health ratings per sensor (`GOOD`, `FAIR`, or `POOR`)	—
`deviceName`	string	Human-readable device name	—
`locationName`	string	Human-readable location name	—

📝
Not all fields are present on every device. Fields are omitted if the device does not have that sensor.

Hub Metadata payload

Published when hub status updates are received. The ${message_type} resolves to metadata.

{
  "serialNumber": "2820012345",
  "recorded": "2026-03-25T22:09:25Z",
  "lastSeenDevices": [
    "3110012345",
    "2969012345",
    "2930112345"
  ],
  "devices": {
    "2930112810": {
      "lastSeen": 1774476565,
      "rssi": -46,
      "type": "wavePlus",
      "productName": "Space Plus"
    },
    "2969040888": {
      "lastSeen": 1774476565,
      "rssi": -41,
      "type": "viewPlusBusiness",
      "productName": "Space Pro"
    },
    "3110006139": {
      "lastSeen": 1774476565,
      "rssi": -48,
      "type": "spaceCo2Mini",
      "productName": "Space CO₂ Mini"
    }
  },
  "connectionType": "ethernet",
  "deviceName": "Office Hub",
  "locationName": "Oslo Location"
}

Field reference

Field	Type	Description
`serialNumber`	string	Hub serial number
`recorded`	ISO 8601	Timestamp of status update
`connectionType`	string/null	`"ethernet"` or `"cellular"` (`null` if unknown)
`lastSeenDevices`	string[]	Serial numbers of connected devices
`devices`	object	Map of serial number to device info
`devices[].lastSeen`	ISO 8601	When device last communicated with hub
`devices[].rssi`	int	Signal strength to hub (dBm)
`devices[].type`	string	Device type identifier
`devices[].productName`	string	Human-readable product name
`deviceName`	string	Human-readable hub name
`locationName`	string	Human-readable location name

Delivery behavior

Property	Details
QoS	0 (at-most-once) — messages are fire-and-forget with no delivery guarantee
Format	Single-line JSON, UTF-8 encoded
Publishing	Each sensor reading is published as a separate MQTT message
Connections	Airthings maintains long-lived persistent connections to your broker and reconnects automatically if the connection drops or configuration changes