If any one come across this issue...
 
I have created custom API with Magento that will be consumed by 3rd party system, which expect fix formate of API response. I have created API data interface and I could able to get formate what they need, but facing problem with JSON associated that API returns,
 
Magento by default changing getter method name into SnakeCase, i.e I have
public function getInvoiceUrl();
this will return
{
  "invoice_url": "string"
}But my expected output is UpperCamelCase like
{
  "InvoiceUrl": "string"
}how can I achieve this with API data interface??
As returning API data with array will return response like,
[{
    "InvoiceUrl": "string"
}]Regards