1. A method comprising: by one or more computing devices, receiving a request for an object from a native system that is missing a value for a property; by one or more computing devices, determining a field mapping for the property for the object comprising: determining a third party object, from a third party system, that matches the object from the native system based on one or more similar other properties; determining that the third party object has a third party value for a third party property that corresponds to the property; determining an incompatibility between a data type of the third party property and the property based on a property specification associated with the property and a property specification associated with the third party; and determining one or more routines to resolve the incompatibility, wherein at least one of the routines transforms the third party value into a normalized value that conforms to the property specification for the property; by one or more computing devices, determining a query for (1) accessing the third party object having the third party property and (2) accessing properties of the object from the native system; by one or more computing devices, in response to receiving the request for the property: executing the query to retrieve the third party value of the third party property from a third party system; and modifying the retrieved third party value of the third party property of the third party object according to the field mapping; and by one or more computing devices, providing, as a response to the request, the object with the value for the property as modified according to the field mapping to provide access to the normalized value from the third party property in the native system through a native call to the property on the object.