To efficiently construct and add a JSON object or array to your request body, use XPRIM_JsonWriter.
It's essential that you use XPRIM_JsonWriter when your JSON data is big (instead of directly instantiating multiple XPRIM_JsonObject or XPRIM_JsonArray), as XPRIM_JsonWriter is designed to perform better for big data.
Define_Com Class(#XPRIM_HttpRequest) Name(#Req)

• Create an XPRIM_JsonWriter to efficiently write JSON data
  Define_Com Class(#XPRIM_JsonWriter) Name(#JsonWriter)
• Set the writer to output the JSON to the HTTP request object
  #JsonWriter.SetOutputToHttpRequest HttpRequest(#Req)
• Start constructing the object
  #JsonWriter.BeginObject
  #JsonWriter.WriteString Name('givenName') Value(#EmpGivenName)
  #JsonWriter.WriteString Name('lastName') Value(#EmpLastName)
  #JsonWriter.WriteString Name('address') Value(#EmpAddress)
  #JsonWriter.EndObject
• Execute the request
  #Req.DoPost Url('http://yourcompany.com/api/hr/employee')
  Next: Creating Multiple Part (Multipart) Body