KML is being widely adopted by applications like Mapufacture, ESRI ArcGIS, Yahoo Pipes, NASA WorldWind, Google Earth, Google Maps, Google Maps Mobile, Flickr and Platial. It's now more important than ever to make sure that your KML files are compliant with the KML standards. Here are two ways to validate your KML.Online Validation with the Feedvalidator
Just go to feedvalidator.org and enter the URL of your KML. The Feed Validator will analyze your KML and where appropriate, will offer suggestions for how to improve your KML. Note that your KML files need to be on a publicly accessible URL to work with feedvalidator.org. If that is a problem for you, then you can install your own copy of Feed Validator (written in Python) and run it on your intranet. Feed Validator also handles RSS and Atom feeds, if you'd like to validate those as well.Offline Validation with XML Schema
You can also validate your KML against the KML Schema . Many XML editors allow for schema validation, or you can download a validating XML parser like Xerces, libxml and validate your KML on the command line or from within your applications.Try out the FeedValidator below!