I am trying to deserialize a request body but need to allow one of the fields to be optional.

RequestBody {
   Decimal someNumber;

RequestBody reqBody = (RequestBody)JSON.deserialize(req.requestBody.toString(), RequestBody.class);

MyCustomObject obj = new MyCustomObject();

obj.someNumber = reqBody.someNumber;

If the field age is empty, it gets sent in as an empty string, and I just get a 500 Server Error as my response. How can I allow this to just be null if it's empty?

  • I Do not see age and not sure about your 500 error you can try this for assignment obj.someNumber = reqBody <> NULL && reqBody.someNumber<> NULL? reqBody.someNumber : NULL; are you saying someNumber is not present whre from you are getting theJSON – Avijit Chakraborty Jan 24 '20 at 3:42
  • In case all values form JSON are comming as strings { "key" : "value" }, you can

Map < String, Object > bodyMap = JSON.deserializeUntyped(req.requestBody.toString());

if (bodyMap.containsKey('age') && String.isNotEmpty((String)bodyMap.get('age')) { obj.someNumber = (Integer) bodyMap.get('age');


do the same for all variables you want to set (look carefuly to cast each value to the proper primitive data types)

  • otherwise you will have to check the values instances

    • bodyMap.get('age') instanceOf String
    • bodyMap.get('age') instanceOf Integer

and properly handle each data type

Good luck!


A number field that is blank should not be sent as an empty string. It should either be omitted entirely or set to the value null (without quotes).

When there's a value:

{ "someNumber": 5 }

When the value is null:

{ "someNumber": null }

Or you can just omit it entirely:

{ }

If you can't control the JSON, then you'll have to use JSON.deserializeUntyped to determine if it is a string or not:

Map<String, Object> reqBody = (Map<String, Object>)JSON.deserializeUntyped(req.requestBody.toString());
Object someValue = reqBody.get("someValue");
if(someValue instanceOf Integer) {
    // Do something with it as a number
    Integer someValueInt = (Integer)someValue;
} else {
    // It's a string, or null, or whatever

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