Yup, in that case I’d make a custom Ecto.Type for serializing/deserializing the xml column between Elixir as binary, and look into erlxml the sdtlib’s xmerl_xsd for XSD validation. You could then consider sweet_xml if you want to use xpath to extract data, or just work with erlxmlxmerl parsing. The xml_builder library should help you build responses and you can pass that back through xmerl_xsd for validation, and a properly implemented Ecto.Type should be capable of serializing resultant binaries back into postgres xml columns.
Truly, you are blessed. 
