You can validate your xml model file against a selected format.
This validation is using libxml2 (http://xmlsoft.org/) to process the xml file using the Format's xsd schema (and dependencies).
After you select the Format your model is for, and upload a model file (*.xml), the file will be validated on this server. Upon completion you should see on top, if it was successful.
The two tabs below show the model file (with annotated errors if there are such). Alternatively, all errors can be inspected as a table.