The xmlschema library is an implementation of XML Schema for Python (supports Python 3.8+).

This library arises from the needs of a solid Python layer for processing XML Schema based files for MaX (Materials design at the Exascale) European project. A significant problem is the encoding and the decoding of the XML data files produced by different simulation software. Another important requirement is the XML data validation, in order to put the produced data under control. The lack of a suitable alternative for Python in the schema-based decoding of XML data has led to build this library. Obviously this library can be useful for other cases related to XML Schema based processing, not only for the original scope.

The full xmlschema documentation is available on “Read the Docs”.


This library includes the following features:

  • Full XSD 1.0 and XSD 1.1 support

  • Building of XML schema objects from XSD files

  • Validation of XML instances against XSD schemas

  • Decoding of XML data into Python data and to JSON

  • Encoding of Python data and JSON to XML

  • Data decoding and encoding ruled by converter classes

  • An XPath based API for finding schema’s elements and attributes

  • Support of XSD validation modes strict/lax/skip

  • XML attacks protection using an XMLParser that forbids entities

  • Access control on resources addressed by an URL or filesystem path

  • Downloading XSD files from a remote URL and storing them for offline use

  • XML data bindings based on DataElement class

  • Static code generation with Jinja2 templates


You can install the library with pip in a Python 3.7+ environment:

pip install xmlschema

The library uses the Python’s ElementTree XML library and requires elementpath additional package. The base schemas of the XSD standards are included in the package for working offline and to speed-up the building of schema instances.


The xmlschema library is distributed under the terms of the MIT License.


This software is hosted on GitHub, refer to the xmlschema’s project page for source code and the issue tracker. For questions, info and announcements refer also to the discussion section of the project page instead of open a new issue.