Use the document’s schema—or select one
Validate using declared XSD or DTD references, assigned schema pools, or a specific schema chosen for the task.
XML validator for Windows
Validate XML against structure and business rules.
Use the dedicated XML validation workflow for XSD, DTD, and Schematron checks, with diagnostics that help you move from a failed document to a verified correction.
- XSDW3C XML Schema checks
- DTDDocument type validation
- SchematronBusiness-rule validation
- BatchFolder and repeatable runs
A complete validation workflow
Choose the rule set, run the check, inspect the result.
Combine structural and business checks
Run XSD or DTD validation and apply Schematron when the workflow needs rule-level assertions.
Move from finding to source
Inspect messages, jump to the affected location, fix the XML, and repeat the validation.
Choose the right XML check
Schema validation goes beyond well-formed XML.
A well-formedness check confirms that the XML syntax can be parsed. This XML validator tests the document against XSD, DTD, or Schematron rules and connects validation findings to the source.
Web API boundary:
POST /api/xml/check checks well-formedness. It does not perform XSD, DTD, or Schematron validation.
Validate XML with the rules your data must satisfy.
Download XML ValidatorBuddy for Windows.
Validation for agents and CI
Run the same deterministic XML check outside the editor.
After testing a validation rule interactively, call ValBuddy locally with explicit schema and input paths. A developer, AI coding agent, or Windows CI runner can gate the next step on the exit status and use the relevant diagnostics to correct a focused issue.
An agent may still send selected content or diagnostics to its model provider. XML processing may use network access when related resources resolve remote references.
More details for this workflow
This is the main XML validator page for XML ValidatorBuddy. Use it when you need a Windows desktop validator for schema-based XML validation, well-formedness checks, large XML files, repeatable batch validation, and detailed reports. If you are ready to install the software, go directly to the download page.
- XML ValidatorBuddy is your W3C XML validator tool with support for all important XML technologies.
- Validate XML against W3C Schema, DTDs, and Schematron.
- Use the same validator to check your W3C schemas.
- Use XML schema catalog functionalities and validate XML instances with no schema assignment.
- Unique one-click Schematron validator.
- Quickly find not well-formed XML data and fix any parsing errors.
Download XML ValidatorBuddy as your XML editor now:
- XML Validator Buddy offers special features for XML batch validation.
- Use the integrated File Explorer to check multiple XML files or folders.
- There is no need to open the XML, just select and run the schema validator.
- You get a comprehensive list of valid or invalid XML documents quickly.
- Select any W3C schema or DTD for XML input with no schema assigned.
- Special validator features for huge data.
- Use the XML validator to find all content or well-formed errors at once.
- Open any XML input in the editor.
- Jump-to-error functionality to locate error positions quickly.
- Rich editor environment with syntax-coloring, code folding, copy-paste, find and replace, XPath evaluation and other standard editing capabilities.
With XML Validator Buddy you can validate and inspect XML data without the need to open them. This is a big advantage compared to other tools which always require to open any XML instance even if you just want to check if the XML is well-formed. Using XML Validator Buddy you only need to select the documents in the built-in File Explorer and start to validate any amount of XML data at once against any schema.