Here you get an overview about the available API function calls, the parameters and the required formats of the parameters.

Only HTML, JSON and XML responses are possible.

https://api.forecast.solar/help

curl -H "Accept: application/json" https://api.forecast.solar/help
wget --header="Accept: application/json" https://api.forecast.solar/help

Try yourself as HTML page: https://api.forecast.solar/help