Send feedback Home Docs App Engine Documentation Standard Environment PHP 5 Reference API Documentation \google\appengine\runtime\ArgumentError Thrown by APIProxy calls if there is an error parsing the arguments. Was this page helpful? Let us know how we did: Send feedback Except as otherwise noted, the content of this page is licensed under the Creative Commons Attribution 4.0 License, and code samples are licensed under the Apache 2.0 License. For details, see our Site Policies. Java is a registered trademark of Oracle and/or its affiliates. Last updated June 3, 2019.