Free XML RELAX NG Validator Online

XML Input

RELAX NG Schema

Validation Result

RELAX NG Validation

If you need a schema language that's simpler and more flexible than W3C XML Schema (XSD), RELAX NG is your answer. Designed as part of the OASIS specification, RELAX NG uses a pattern-based approach to define XML grammars -- you describe what valid documents look like instead of listing constraints. This tool validates your XML against RELAX NG schemas by resolving the start rule, checking root element compatibility, and verifying required child elements. Everything runs in your browser's XML parser, so nothing leaves your machine.

How to Use the XML RelaxNG Validator

Paste Your XML Document

Copy the XML you want to validate and paste it into the XML input panel. The document should be well-formed XML.

Paste the RelaxNG Schema

Paste the RelaxNG schema (compact or XML syntax) into the schema panel. The schema defines the expected structure of your XML.

Validate and Fix Errors

Click Validate. Any violations are highlighted with clear error messages pointing to the exact location in your XML that does not match the schema.

Example

Example: Simple address book validation

XML document:

<addressBook>
  <card>
    <name>Alice</name>
    <email>[email protected]</email>
  </card>
</addressBook>

RelaxNG schema (compact syntax):

element addressBook {
  element card {
    element name { text },
    element email { text }
  }+
}

Frequently Asked Questions

How do I validate XML against RELAX NG online?

Paste your XML in the left panel and your RELAX NG schema in the right panel, then click Validate. The tool resolves the start rule and checks your document structure against the schema patterns -- all locally in your browser.

What is the difference between RELAX NG and XSD?

RELAX NG uses a simpler, pattern-based approach to define XML structure, while XSD offers richer datatype constraints and namespace support. RELAX NG is often easier to read and write by hand.

Is my XML data sent to a server?

No. All RELAX NG validation runs entirely in your browser. Your XML and schema never leave your machine, making it safe for production data and sensitive documents.

Does this support RELAX NG compact syntax?

This tool works with RELAX NG XML syntax schemas. For compact syntax (.rnc files), you'll need to convert to XML syntax first using a tool like trang.

When should I choose RELAX NG over DTD or XSD?

Choose RELAX NG when you want a clean, readable schema that's easier to maintain than XSD but more expressive than DTD. It's especially good for document-centric XML like XHTML, DocBook, and OpenDocument formats.