question

Yes, you need to do it using http request node.

function -> http request (GET) -> json

const VRM_ID = "XXXXXX";
const VRM_ACCESS_TOKEN = "XXXXXXXXXXXXXXXX";

let today = new Date();

let startDate = new Date(today.getFullYear(), today.getMonth(), today.getDate(), 0, 0, 0, 0);
let endDate = new Date(today.getFullYear(), today.getMonth(), today.getDate(), 23, 59, 59, 999);

let start = Math.floor(startDate.getTime() / 1000);
let end = Math.floor(endDate.getTime() / 1000);

return [
    {
        'url': "https://vrmapi.victronenergy.com/v2/installations/" + VRM_ID + "/stats?type=forecast&interval=hours&start=" + start + "&end=" + end,
        'headers': {
            'x-authorization': "Token " + VRM_ACCESS_TOKEN
        }
    }
];

You can use the flow as shown below:

After injecting the timestamp, the information on the solar yield gets fetched:

The records part shows, per hour, the expected yield. The first field in that hourly array is the timestamp, the second one the expected yield for that hour.

The totals shows the expected totals for the day. Note that this only works on sites that produce solar. If your site does not produce solar, the records and totals will show 'false':

For full reference: