I am looking for a custom reference key to use with my application via the Twilio SMS API. To crosscheck my request, I need a reference number generated at my end to send in a rest request and get the same in response.
Is there any way Twilio allows custom parameter in the request?
Unfortunately you cannot add custom parameters in Twilio.
You are correct in that the only way you would be able to do this is add the parameters to the querystring and we would just pass those parameters along to your application. May be in future release they will come up with custom parameters feature.