XML Validator: Check XML Syntax and Locate Errors Online
XML Validator checks whether pasted or dropped XML is well-formed, then reports syntax problems with their line and column and a code frame. It uses the browser's DOMParser for this check, so you can quickly locate malformed markup before passing a document to another parser. It does not validate XML against an XSD or DTD; schema validation is not available.
XML Validator is a browser-based XML validation tool for checking whether a document is well-formed. Paste or drop XML to get a check that reports syntax errors with a line, column, and code frame. Use it to find malformed markup before sending a document to another parser or investigating a runtime failure.
The well-formedness check uses the browser's DOMParser. When the input contains a syntax problem, the tool reports where the error occurs so you can inspect the relevant part of the document. This checks XML syntax; it does not determine whether the document follows a particular schema or meets an application's data requirements.
XML uses markup with elements, attributes, and text content. Well-formed XML must follow the format's structural rules, while an XSD or DTD can define additional rules for a particular document type. This tool does not provide XSD or DTD validation; that capability is not yet available and requires a WASM validator. Use the check to catch malformed XML, but use schema validation when you need to test against a specific XSD or DTD.
XML Validator runs entirely in your browser. Your input is processed on your device and is not uploaded, stored, or sent to a server. Once the page has loaded, the tool works offline without a server connection.
This XML Validator is useful for developers and DevOps engineers checking files before a parser consumes them, diagnosing syntax errors, or reviewing XML generated by another tool. Its line, column, and code frame make it easier to focus on the location that needs attention.
Step 1: Paste or drop your XML into the tool. Use the document you want to check, including its markup and attributes.
Step 2: Run the check to test whether the XML is well-formed. The tool uses the browser's DOMParser for this check.
Step 3: Review the result. If the XML has a syntax error, use the reported line, column, and code frame to locate it.
Step 4: Correct the malformed markup in your source, then run the check again to confirm the XML is well-formed.
Use case: Check an XML file before it reaches a parser and fails at runtime. Finding a well-formedness issue early can make troubleshooting easier.
Use case: Locate a syntax error by its reported line and column instead of searching through the file by hand.
Use case: Confirm that XML generated by another tool is well-formed, rather than relying on how the output looks.
Use case: Check XML received from a service or another developer before using it in your workflow.
Use case: Inspect an XML document while debugging a parsing problem. The code frame helps you focus on the reported error location.
Use case: Run a quick XML syntax check before sharing a document or passing it to another parser.