hi,
Mendix Import Mappings require a fixed JSON schema and do not support mixed or dynamic value types in the same field. In your example:
"product_id": [1, "sample"]
This array contains both an integer and a string — that is not supported by Mendix import mapping. The JSON parser determines type based on the first element and expects the rest to be the same type. Mixed arrays like this are flagged as unsupported.
Transform the REST response into a consistent format before import mapping:
product_id always has two parts (id and name), handle it as a list of strings:"product_id": ["1", "sample"]
"product_id": {"id": 1, "name": "sample"}
Id and Name.This restructure must happen before the Import Mapping step.
If the structure truly varies and you cannot predict it:
This bypasses Import Mapping, giving full control over mixed types.
For truly dynamic or deeply inconsistent JSON:
JsonNode or similar toolsThese approaches avoid strict import mapping and let you handle any type.
https://community.mendix.com/link/spaces/integrations/questions/140171
Expert Stephan’s solution in this link directly addresses your issue with mapping array-type fields. He explains that Mendix cannot handle dynamic attributes where the same field has different types (for example, sometimes a number and sometimes an array). Instead of mapping the array field directly in the Import Mapping, he recommends storing the raw JSON as a string and then extracting the dynamic values using JSON Path or additional parsing logic.
This approach applies to your case as well, because your product_id field is returned as an array with mixed types. Therefore, instead of trying to map it directly, you should handle it separately using JSON Path or custom parsing after receiving the response.