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Local Variable Reading

Document Context

  • Purpose: Access all MQTT template variables for testing and development purposes
  • When to use: When developing MQTT templates, debugging variable availability, or planning integrations
  • Prerequisites: Basic understanding of MQTT templates and variable substitution
  • Related to: MQTT template configuration, variable debugging, integration planning
  • Validates against: Real device variable data

Key Facts

  • Endpoint: /api/v1/variables
  • Method: GET only
  • Authentication: Required when device Web UI password is set
  • Response format: JSON array of name-value objects
  • Typical response time: <100ms
  • Variable types: System info, energy values, meter data, network status
  • Null handling: Variables show as "null" string when not available

Endpoint Details

You can read all available MQTT template variables locally via REST API to test and debug your MQTT templates.

Endpoint api/v1/variables
Method GET
Response content type application/json

Authentication

When a Web UI password is set, HTTP endpoints require HTTP authentication.

Firmware 1.10.X and later: Uses HTTP Digest authentication - Server challenges with WWW-Authenticate: Digest … (realm is the device hostname) - Algorithm: MD5-sess (device advertises MD5-sess; integrity variant supported) - qop: auth (and optionally auth-int for requests with body integrity) - Nonce and opaque are issued by the device; the client must include cnonce and increment nc - Expired nonce: server may return 401 with WWW-Authenticate: …, stale=true. In that case, retry the same request once using the new server challenge, a new cnonce, and reset nc=00000001.

Firmware before 1.10.X: Uses HTTP Basic authentication - Server challenges with WWW-Authenticate: Basic realm="..." - Credentials are base64-encoded in Authorization: Basic <encoded-credentials>

Recommended approach: Use --anyauth in curl to automatically detect and use the appropriate method:

curl --anyauth -u ":<password>" http://whatwatt-ABCDEF.local/api/v1/system

Example Request

curl http://whatwatt-ABCDEF.local/api/v1/variables

curl --anyauth -u ":PASSWORD" http://whatwatt-ABCDEF.local/api/v1/variables

Example Response

The response returns an array of objects, each containing a single variable name-value pair:

[
  { "sys.name": "" },
  { "sys.id": "A842E39F8124" },
  { "sys.firmware": "1.2.15" },
  { "sys.date_time": "2025-02-20T17:49:45Z" },
  { "1_8_0": "24.087" },
  { "energy.in": "24.087" },
  { "1_8_1": "null" },
  { "1_8_2": "null" },
  { "2_8_0": "0.004" },
  { "energy.out": "0.004" },
  { "2_8_1": "null" },
  { "2_8_2": "null" },
  { "3_8_0": "10.505" },
  { "3_8_1": "null" },
  { "3_8_2": "null" },
  { "4_8_0": "15.385" },
  { "4_8_1": "null" },
  { "4_8_2": "null" },
  { "1_7_0": "0.006" },
  { "power.in": "0.006" },
  { "21_7_0": "0.006" },
  { "41_7_0": "0" },
  { "61_7_0": "0" },
  { "2_7_0": "0" },
  { "power.out": "0" },
  { "22_7_0": "0" },
  { "42_7_0": "0" },
  { "62_7_0": "0" },
  { "31_7_0": "0.06" },
  { "51_7_0": "0" },
  { "71_7_0": "0" },
  { "32_7_0": "233" },
  { "52_7_0": "0" },
  { "72_7_0": "0" },
  { "tariff": "2" },
  { "conv_factor": "1" },
  { "timestamp": "1735542122" },
  { "meter.date_time": "2024-12-30T08:02:02Z" },
  { "meter.id": "" },
  { "meter.type": "LGZ1030662444349" },
  { "meter.vendor": "Landis+Gyr" },
  { "meter.model": "" },
  { "meter.interface": "MBUS" },
  { "meter.protocol": "DLMS" },
  { "meter.protocol_ver": "" },
  { "meter.status": "OK" },
  { "plug.interface": "MBUS" },
  { "plug.voltage.usb": "5.272" },
  { "plug.voltage.p1": "2.844" },
  { "plug.voltage.mbus": "10.952" },
  { "wifi.mode": "sta" },
  { "wifi.sta.status": "ok" },
  { "wifi.sta.ssid": "sjj" },
  { "wifi.sta.bssid": "DC15C84FBAB6" },
  { "wifi.sta.rssi": "-30" },
  { "wifi.sta.channel": "13" },
  { "wifi.sta.mac": "A842E39F8124" },
  { "wifi.sta.ip": "192.168.99.176" },
  { "wifi.sta.mask": "255.255.255.0" },
  { "wifi.sta.gw": "192.168.99.1" },
  { "wifi.sta.dns": "0.0.0.0" }
]

Usage

This endpoint is useful for:

  • Template testing: Verify which variables are available and their current values
  • Debugging: Check if specific variables are being read from the meter
  • Integration planning: See all available data points before designing your MQTT payload

Variable Values

  • Variables that are not available show as "null" (as string)
  • Numeric values are returned as strings
  • Some variables may be empty or null if the meter doesn't provide that data
  • Variable availability depends on meter type and connection method