> For the complete documentation index, see [llms.txt](https://doc.orbeon.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://doc.orbeon.com/form-builder/advanced/xml-schema-support.md).

# XML Schemas support

## Availability

This is an [Orbeon Forms PE](https://www.orbeon.com/download) feature.

## Working with an XML Schema

The toolbox's "XML Schema" button under the "Advanced" tab allows you to attach an XML Schema to the form. This serves two purposes:

* The schema is used to validate the form data.
* Simple types present in the schema are made available in the Validation Details dialog.

NOTE: Form Builder does not handle imported/included sub-schemas. If you attempt to attach such a schema, a warning message is displayed.