In the SAP and Microsoft world, OData V4 is quite common. This is a Rest interface with metadata (date datatype!!), filters, pagination and much more. So perfectly suited to serve as alternative to the simple JSONParser for parsing external data via chart.dataSource.url.
There is even a Javascript library.
https://olingo.apache.org/
Just one additional thought: Although olingo as a library can be used, you do not have to. The user provides a oData URL and the result is data in an easy to parse Json format.
In the SAP and Microsoft world, OData V4 is quite common. This is a Rest interface with metadata (date datatype!!), filters, pagination and much more. So perfectly suited to serve as alternative to the simple JSONParser for parsing external data via chart.dataSource.url. There is even a Javascript library. https://olingo.apache.org/
Just a thought.