I cannot tell you how many issues I see come up in the AdWords API forum about why does a certain request work in the Google AdWords API Sandbox and not in the normal AdWords API. A Sandbox API is a test ground for developers to test out new code changes without impacting live data.
Eric Koleda from the AdWords API Team announced in a AdWords API Help thread the introduction of enhanced XML validation for the AdWords API sandbox. That means, the XML you use in the sandbox will be stricter and return more detailed errors when it does not validate. Let me quote Eric:
Yesterday we enabled an enhanced form of XML validation on the AdWords API sandbox that returns more detailed error messages for incorrectly formatted SOAP XML requests. This new validation mechanism is more strict and enforces rules that were previously ignored. Most SOAP libraries already conform to these rules, but requests that are constructed manually may now return validation errors. Some key changes in the validation logic are:
* The fields of an object must be in the correct order. The order of the fields is defined in the WSDL and reflected in our developer documentation. * The namespaces used in the request body must be declared on the method element (get, mutate, etc). If all of the namespace prefixes are declared on the SOAP envelope element you must ensure they are re- defined on the method element.
For right now this will only be enabled in the sandbox to give you time test your code against this new type of validation. If you have any questions or issues please let us know.
Forum discussion at AdWords API Help.