What does DTD validation check here?

This tool checks whether XML elements are declared in DTD, whether root is declared, and whether required children exist in simple sequence models.

Does this support every DTD feature?

It focuses on practical checks for quick debugging. Advanced DTD constructs may require dedicated validators.

Can I paste inline DTD declarations?

Yes. Paste DTD declarations directly in the DTD panel and validate against your XML input.

Yes. Validation runs in your browser and XML/DTD content is not sent to a server.

Should I use DTD or XSD?

DTD is simpler and common in legacy workflows. XSD is generally richer for datatype and schema constraints.

XML DTD Validator - Validate XML Against DTD Online

XML Input

DTD Input

Validation Result

What Is XML DTD Validation?

DTD (Document Type Definition) is the classic XML grammar mechanism. It declares allowed elements, ordering, and text content rules. DTD is still common in legacy enterprise feeds, publishing workflows, and toolchains that rely on DOCTYPE based validation.

This validator helps you quickly verify practical DTD alignment: root declaration presence, undeclared elements, and missing required children in straightforward sequence models. For richer type constraints and modern contracts, use XML XSD Validator.

How to Use This Tool

Paste XML and DTD

Add XML in the left panel and DTD declarations in the middle panel. Start with sample content if you need a quick template.

Run DTD Checks

Click Validate to compare declared elements against the XML document structure.

Fix and Re-run

Resolve missing declarations or missing required child nodes, then validate again. Use XML Tree Viewer to inspect hierarchy before editing DTD rules.

DTD vs XSD

DTD is compact and widely supported in old systems, but it has limited datatype control. XSD is more expressive and namespace-friendly. If you are modernizing XML pipelines, validate quickly with DTD first, then migrate contracts to XSD where possible.

Frequently Asked Questions

Can I use this for inline DOCTYPE DTD snippets?

Yes. Paste declarations directly into the DTD panel and validate against XML input.

Does this support all DTD grammar constructs?

It focuses on practical checks for fast debugging. Advanced content models may need specialized validators.

Is my content private?

Yes. XML and DTD processing is local in your browser.

When should I choose DTD over XSD?

Choose DTD when maintaining legacy systems. Choose XSD for stronger schema constraints and datatype modeling.

What other checks should I run?

Run XML Validator for syntax first, then use this page for DTD structure checks.

Related Tools

References: XML 1.0, XML 1.1, DTD in XML spec, MDN XML Guide.