MQTT Client Configuration¶

The device can connect to an MQTT broker using the built‑in client. Both unencrypted (mqtt://) and TLS encrypted (mqtts://) connections are supported.

Publish Condition

The device publishes measurement values only when a meter is connected.

Configuration Endpoint¶

Endpoint	`api/v1/mqtt/settings`
Method	GET, POST, PUT
Response content type	application/json

Settings Object Fields¶

Field	Type	Default	Range	Remarks
`.enable`	boolean	false		Enables or disables the MQTT client.
`.url`	string	empty string	0..127, starts with `mqtt://` or `mqtts://`	`mqtt` – not encrypted TCP; `mqtts` – encrypted TLS.
`.username`	string	empty string	0..127	Unique client username.
`.password`	string	empty string	0..127	Not returned on GET; instead `password_len` shows length (0 = not set).
`.client_id`	string	empty string	0..63	Must be unique per broker; duplicate IDs cause prior session disconnect.
`.skip_cn_check`	boolean	false		Skips certificate Common Name validation.
`.publish.topic`	string	empty string	0..127	Target topic for published messages.
`.publish.template`	string	empty string	0..1023	Payload template (text; often JSON).
`.broker.certificate`	string	null		Broker CA/server certificate in PEM (optional).
`.client.certificate`	string	null		Client certificate in PEM (for mutual TLS; requires `.client.key`).
`.client.key`	string	null		Client private key (PEM). Not returned on GET; `key_len` reports length.
`.client.key_password`	string	null	0..255	Password for encrypted private key; not returned on GET (`key_password_len`).

Payload Size Limit

POST/PUT JSON maximum size: 8 kB.

Example Response (GET)¶

{
  "enable": false,
  "url": "mqtts://broker.example.com",
  "username": "demo",
  "client_id": "device123",
  "skip_cn_check": false,
  "publish": {
    "topic": "test",
    "template": "{\n  \"P_In\": ${1_7_0},\n  \"P_Out\": ${2_7_0},\n  \"E_In\": ${1_8_0},\n  \"E_Out\": ${2_8_0},\n  \"Meter\": {\n    \"DateTime\": \"${meter.date_time}\"\n  },\n  \"Sys\": {\n    \"Id\": \"${sys.id}\"\n  }\n}"
  },
  "password_len": 0
}

Updating Configuration¶

POST full object to replace entire configuration.
PUT partial object to update specific fields (existing secret values retained).
Set any certificate/key/password field to null to delete it.
Reporting period (default 30 s) stretches if meter reports less frequently; adjustable in System > Interval to Systems.

Template & Variables¶

See MQTT Template for the full variable list, examples, and guidance on quoting and substitution.

Tips

Treat missing fields as unavailable; don’t assume zero means present.
Quote text variables, don’t quote numeric variables in templates.
Shortly after power‑on some values may be null or empty until available.