How to have null/empty value json via export/import mapping.

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I have export mapping that uses json as the scema source. When try to map the entity with empty attribute values...the export mapping is removing the empty keys. For example for the map if i only add 'firstName' and keep the 'age' attribute empty then the return json is:{"firstName":"Aniket","lastWorkDay":"2026-08-12T09:30:13.109Z"}Here is what i want: {"firstName":"Aniket","age":,"lastWorkDay":"2026-08-12T09:30:13.109Z"}
asked
3 answers
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Hi Aniket,

You can do the following;


  • Create a data transform microflow.




  • Call the microflow in the export mapping



Now the empty attributes won't be skipped, instead it'll give the below;

{

"Name": "",

"Age": ""

}


Note: I your case I see that you use Age as interger. It is best to handle Json attributres as string, incase you want it as integer you have to return as 0 instead of '' in transform microflow.


Hope my answer helps. Reach me out for any queries.

answered
0

Hi Aniket,

Have you tried this setting in the export mapping?

It is part of the properties (propertie pane) of the export mapping document.


answered
0

Hi Aniket,

In this case, the JSON you're expecting is not valid JSON:

{
  "firstName": "Aniket",
  "age":,
  "lastWorkDay": "2026-08-12T09:30:13.109Z"
}


If age is empty, the valid representation should be:

{
  "firstName": "Aniket",
  "age": null,
  "lastWorkDay": "2026-08-12T09:30:13.109Z"
}


For an Export Mapping, Mendix can omit an optional element when its value is empty. The mapping documentation also mentions the Send empty values option for optional/nillable elements.


So I would check whether your JSON structure's age element is configured as optional/nillable and whether Send empty values is enabled.


If the receiving API specifically requires "age": null, make sure the schema allows null and configure the mapping to send empty values rather than omitting the property.


Also note that empty string and null are different values; for an Integer attribute such as age, null is the appropriate JSON representation when there is no value.


Kindly mark this as the accepted answer if it helps.

answered