We Analyzed the Salesforce platform to create an API receiver, the usual way is to Create the wrapper classes that can parse a JSON response in apex using a tool such as ” https://json2apex.herokuapp.com/”. 

Once these wrapper classes are generated, the next step is to write a Receiver class where we need to deserialize the input json string using JSON.deserialize() and it will return an instance of the wrapper class. 

” Now the limitation here with a Wrapper class approach was that, if a new Name/Value pair is added to the Inbound JSON, the wrapper class has to be updated and also for saving New Values in a Custom field on a Custom object, this assignment has to be added, again a code change.”

Solution in Salesforce

To cater the above problem we Used Custom Metadata instead of the Apex because we can utilize a Custom Metadata to map a json Key (name in Name/value pair) to a Custom Field on a Custom Object. 

Now while deserializing the Inbound Json, we have to deserialize it into a Generic type such as Map<String, Object>. Then this Generic Map where we have deserialized the data can be used in conjunction with the metadata records to create/update appropriate Custom field. 

In this approach if a new Name/Value pair is added to the inbound JSON, we have to create a new mapping in the custom metadata and no underlying code change Required.