> 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/xforms/xpath/extension-functions.md).

# Extension functions

- [Core functions](https://doc.orbeon.com/xforms/xpath/extension-functions/extension-core.md)
- [Utility functions](https://doc.orbeon.com/xforms/xpath/extension-functions/extension-util.md)
- [Model functions](https://doc.orbeon.com/xforms/xpath/extension-functions/extension-model.md)
- [Controls functions](https://doc.orbeon.com/xforms/xpath/extension-functions/extension-controls.md)
- [XML functions](https://doc.orbeon.com/xforms/xpath/extension-functions/extension-xml.md)
- [JSON functions](https://doc.orbeon.com/xforms/xpath/extension-functions/extension-json.md)
- [HTTP functions](https://doc.orbeon.com/xforms/xpath/extension-functions/extension-http.md)
- [Form Runner functions](https://doc.orbeon.com/xforms/xpath/extension-functions/extension-form-runner.md)
- [Other functions](https://doc.orbeon.com/xforms/xpath/extension-functions/extension-other.md)
- [Deprecated functions](https://doc.orbeon.com/xforms/xpath/extension-functions/deprecated-functions.md)