The eSciDoc Validation Service checks XML metadata for syntactical and semantical correctness. This is done by a Schematron validation based on a given validation template that is selected by the validation schema id and the given validation point [more].
There are several ways to access the service. Below are links to the REST frontend and the SOAP frontend.
There is also an EJB3 interface called
There is a rudimentary SQL interface to edit validation schemas here.