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Web API

Information in JSON format can be obtained through the web API.

Important Note

The WebAPI is mainly generated to fetch and post information between the WebUI and the ESP. You use it at your own risk. It may change in future and break compatibility!

List of URLs

may be incomplete

GET/POST Auth required URL
Get yes /api/file/get
Post yes /api/file/delete
Get yes /api/file/list
Post yes /api/file/upload
Get+Post yes /api/device/config
Get no /api/devinfo/status
Get+Post yes /api/dtu/config
Get no /api/eventlog/status?inv=inverter-serialnumber
Post yes /api/firmware/update
Get yes /api/inverter/list
Post yes /api/inverter/add
Post yes /api/inverter/del
Post yes /api/inverter/edit
Post yes /api/limit/config
Get no /api/limit/status
Get no /api/livedata/status?inv=inverter-serialnumber
Get no /api/livedata/status
Post yes /api/maintenance/reboot
Get+Post yes /api/mqtt/config
Get no /api/mqtt/status
Get+Post yes /api/network/config
Get no /api/network/status
Get+Post yes /api/ntp/config
Get no /api/ntp/status
Get+Post yes /api/ntp/time
Get no /api/power/status
Post yes /api/power/config
Get no /api/prometheus/metrics
Get+Post yes /api/security/config
Get yes /api/security/authenticate
Get no /api/system/status

Examples of Use

Important notes

  • IP addresses and serial numbers in this examples are anonymized. Adjust to your own needs.
  • The output from curl is without a linefeed at the end, so please be careful when copying the output - do not accidentally add the shell prompt directly after it.
  • When POSTing config data to OpenDTU, always send all settings back, even if only one setting was changed. Sending single settings is not supported and you will receive a response {"type":"warning","message":"Values are missing!"}
  • When POSTing, always put single quotes around the data part. Do not confuse the single quote ' with the backtick `. You have been warned.
  • Some API calls have a single URL for GET and POST - e.g. /api/ntp/config
  • Other API calls use e.g. /api/limit/status to GET data and a different URL /api/limit/config to POST data.
  • If you want to investigate the web api communication, a good tool is Postman
  • Settings API require username and password provided with Basic Authentication credentials
  • If you disable the readonly access to the web API, every endpoint requires authentication

Get information

You can "talk" to the OpenDTU with a command line tool like curl. The output is in plain JSON, without carriage return/linefeed and is therefore not very human readable.

Get common live data

$ curl http://192.168.10.10/api/livedata/status
{"inverters":[{"serial":"1161716xxxxx","name":"Meine Solaranlage","order":0,"data_age":30636,"poll_enabled":true,"reachable":false,"producing":false,"limit_relative":100,"limit_absolute":1500},{"serial":"1141716xxxxx","name":"Inverter 2","order":0,"data_age":108349,"poll_enabled":false,"reachable":false,"producing":false,"limit_relative":0,"limit_absolute":-1},{"serial":"1141716xxxxx","name":"Inverter 3","order":0,"data_age":108349,"poll_enabled":false,"reachable":false,"producing":false,"limit_relative":0,"limit_absolute":-1}],"total":{"Power":{"v":0,"u":"W","d":1},"YieldDay":{"v":0,"u":"Wh","d":0},"YieldTotal":{"v":2515.605957,"u":"kWh","d":3}},"hints":{"time_sync":false,"radio_problem":false,"default_password":false}}

To enhance readability (and filter information) use the JSON command line processor jq.

$ curl --no-progress-meter http://192.168.10.10/api/livedata/status | jq
{
  "inverters": [
    {
      "serial": "1161716xxxxx",
      "name": "Meine Solaranlage",
      "order": 0,
      "data_age": 30687,
      "poll_enabled": true,
      "reachable": false,
      "producing": false,
      "limit_relative": 100,
      "limit_absolute": 1500
    },
    {
      "serial": "1141716xxxxx",
      "name": "Inverter 2",
      "order": 0,
      "data_age": 108400,
      "poll_enabled": false,
      "reachable": false,
      "producing": false,
      "limit_relative": 0,
      "limit_absolute": -1
    },
    {
      "serial": "1141716xxxxx",
      "name": "Inverter 3",
      "order": 0,
      "data_age": 108400,
      "poll_enabled": false,
      "reachable": false,
      "producing": false,
      "limit_relative": 0,
      "limit_absolute": -1
    }
  ],
  "total": {
    "Power": {
      "v": 0,
      "u": "W",
      "d": 1
    },
    "YieldDay": {
      "v": 0,
      "u": "Wh",
      "d": 0
    },
    "YieldTotal": {
      "v": 2515.605957,
      "u": "kWh",
      "d": 3
    }
  },
  "hints": {
    "time_sync": false,
    "radio_problem": false,
    "default_password": false
  }
}

Get inverter detail livedata

$ curl http://192.168.10.10/api/livedata/status?inv=1161716xxxxx
{"inverters":[{"serial":"1161716xxxxx","name":"Meine Solaranlage","order":0,"data_age":30824,"poll_enabled":true,"reachable":false,"producing":false,"limit_relative":100,"limit_absolute":1500,"AC":{"0":{"Power":{"v":0,"u":"W","d":1},"Voltage":{"v":0,"u":"V","d":1},"Current":{"v":0,"u":"A","d":2},"Frequency":{"v":0,"u":"Hz","d":2},"PowerFactor":{"v":0,"u":"","d":3},"ReactivePower":{"v":0,"u":"var","d":1}}},"DC":{"0":{"name":{"u":""},"Power":{"v":0,"u":"W","d":1},"Voltage":{"v":0,"u":"V","d":1},"Current":{"v":0,"u":"A","d":2},"YieldDay":{"v":0,"u":"Wh","d":0},"YieldTotal":{"v":834.2609863,"u":"kWh","d":3},"Irradiation":{"v":0,"u":"%","d":3,"max":385}},"1":{"name":{"u":""},"Power":{"v":0,"u":"W","d":1},"Voltage":{"v":0,"u":"V","d":1},"Current":{"v":0,"u":"A","d":2},"YieldDay":{"v":0,"u":"Wh","d":0},"YieldTotal":{"v":832.7069702,"u":"kWh","d":3},"Irradiation":{"v":0,"u":"%","d":3,"max":385}},"2":{"name":{"u":""},"Power":{"v":0,"u":"W","d":1},"Voltage":{"v":0,"u":"V","d":1},"Current":{"v":0,"u":"A","d":2},"YieldDay":{"v":0,"u":"Wh","d":0},"YieldTotal":{"v":843.7299805,"u":"kWh","d":3},"Irradiation":{"v":0,"u":"%","d":3,"max":385}},"3":{"name":{"u":""},"Power":{"v":0,"u":"W","d":1},"Voltage":{"v":0,"u":"V","d":1},"Current":{"v":0,"u":"A","d":2},"YieldDay":{"v":0,"u":"Wh","d":0},"YieldTotal":{"v":4.907999992,"u":"kWh","d":3}}},"INV":{"0":{"Power DC":{"v":0,"u":"W","d":1},"YieldDay":{"v":0,"u":"Wh","d":0},"YieldTotal":{"v":2515.605957,"u":"kWh","d":3},"Temperature":{"v":0,"u":"°C","d":1},"Efficiency":{"v":0,"u":"%","d":3}}},"events":2}],"total":{"Power":{"v":0,"u":"W","d":1},"YieldDay":{"v":0,"u":"Wh","d":0},"YieldTotal":{"v":2515.605957,"u":"kWh","d":3}},"hints":{"time_sync":false,"radio_problem":false,"default_password":false}}

The eventlog can be fetched with the inverter serial number as parameter:

$ curl --no-progress-meter http://192.168.10.10/api/eventlog/status?inv=11418186xxxx | jq
{
  "11418186xxxx": {
    "count": 4,
    "events": [
      {
        "message_id": 1,
        "message": "Inverter start",
        "start_time": 28028,
        "end_time": 28028
      },
      {
        "message_id": 209,
        "message": "PV-1: No input",
        "start_time": 28036,
        "end_time": 0
      },
      {
        "message_id": 2,
        "message": "DTU command failed",
        "start_time": 28092,
        "end_time": 28092
      },
      {
        "message_id": 207,
        "message": "MPPT-A: Input undervoltage",
        "start_time": 28336,
        "end_time": 0
      }
    ]
  }
}

combine curl and jq

jq can filter specific fields from json output.

For example, filter out the current total power:

$ curl --no-progress-meter http://192.168.10.10/api/livedata/status | jq '.total | .Power.v'
140.7999878

Get information where login is required

When config data is requested, username and password have to be provided to curl Username is always admin, the default password is openDTU42. The password is used for both the admin login and the Admin-mode Access Point.

$ curl --u admin:openDTU42 http://192.168.10.10/api/ntp/config
{"ntp_server":"pool.ntp.org","ntp_timezone":"CET-1CEST,M3.5.0,M10.5.0/3","ntp_timezone_descr":"Europe/Berlin"}

Post information

With HTTP POST commands information can be written to the OpenDTU.

The Web API is designed to allow the web frontend in the web browser to communicate with the OpenDTU software running on the ESP32. It is not designed to be intuitive or user-friendly, so please follow the instructions here.

Example 1: change ntp settings

If you want to configure the ntp server setting, first fetch the information from the web API:

$ curl -u "admin:password" http://192.168.10.10/api/ntp/config
{"ntp_server":"pool.ntp.org","ntp_timezone":"CET-1CEST,M3.5.0,M10.5.0/3","ntp_timezone_descr":"Europe/Berlin"}

Then, second step, send your new settings. Use the text output from curl in the first step, add data= and enclose the whole data with single quotes.

$ curl -u "admin:password" http://192.168.10.10/api/ntp/config -d 'data={"ntp_server":"my.own.ntp.server.home","ntp_timezone":"CET-1CEST,M3.5.0,M10.5.0/3","ntp_timezone_descr":"Europe/Berlin"}'
{"type":"success","message":"Settings saved!"}

You will receive a json formatted response.

Example 2: change power limit

In the second example, I want to change the non persistent power limit of an inverter. Again, first fetch current data:

$ curl http://192.168.10.10/api/limit/status
{"11418186xxxx":{"limit_relative":100,"max_power":600,"limit_set_status":"Ok"},"11418180xxxx":{"limit_relative":100,"max_power":800,"limit_set_status":"Ok"}}

I see data from two configured inverters.

Now I set the relative power limit of inverter with serialnumber 11418180xxxx to 50%.

$ curl -u "admin:password" http://192.168.10.10/api/limit/config -d 'data={"serial":"11418180xxxx", "limit_type":1, "limit_value":50}'
{"type":"success","message":"Settings saved!"}

Then I read again the limit status. In the first answer the status is pending, some seconds later it changed to OK.

$ curl http://192.168.10.10/api/limit/status
{"11418186xxxx":{"limit_relative":100,"max_power":600,"limit_set_status":"Ok"},"11418180xxxx":{"limit_relative":100,"max_power":800,"limit_set_status":"Pending"}}

...

$ curl http://192.168.10.10/api/limit/status
{"11418186xxxx":{"limit_relative":100,"max_power":600,"limit_set_status":"Ok"},"11418180xxxx":{"limit_relative":50,"max_power":800,"limit_set_status":"Ok"}}