Passing POST value in REST API

Hi,

We are using SoapUI for testing REST APIs.

If API requires single parameter (lets say name) for POST operation, SoapUI accepts in this format: name=testing123 but rejects in this format: {"name" : "testing123"}

If API required multiple parameter (lets say name and age) for POST operation, SoapUI rejects in this format: name=testing123,age=20 but accepts in this format: {"name" : "testing123", "age" : "20"}

Can someone help me understanding this problem.

Thanks.