Online XML Formatter & Validator
Paste raw or minified XML to get a properly indented, readable version, or strip it down to the smallest possible size. Validate checks well-formedness — matching tags and valid structure — and reports the first error it finds, rather than silently producing garbage output on malformed input the way some tools do. It helps developers inspect SOAP responses, XML feeds, and configuration files when compact markup hides the document structure.
How to format XML online
Paste raw or minified XML into the input box. Click Format to get a properly indented, readable version with each element on its own line — much easier to scan than a single unbroken line of tags. Click Minify to go the other way, stripping all whitespace between tags down to the smallest possible size. Click Validate to check well-formedness without reformatting anything.
What "well-formed" actually means
Well-formed XML means every opening tag has a matching closing tag, elements are properly nested (no overlapping tags), there's exactly one root element, and attribute values are quoted. This is a lower bar than validating against a specific schema (XSD or DTD) — the validator here confirms the XML's basic structure is sound, not that it conforms to a particular document type.
A note on error handling
The browser's native DOMParser never throws an exception on malformed XML — it silently returns a document containing an embedded error node instead. This tool explicitly checks for that error node and reports it clearly, rather than letting malformed input silently "succeed" and produce garbage output, which is a common pitfall when working with DOMParser directly.
Common use cases
- Making a minified SOAP or REST XML response readable for debugging
- Checking whether a hand-edited XML config file is still well-formed before deploying it
- Shrinking an XML payload before sending it over a bandwidth-constrained connection
How to use XML Formatter for related tasks
Format XML for debugging, validate its syntax, or minify XML before sending it as a compact payload.
Related tools: XML/XSD Validator, JSON ↔ YAML Converter.
Frequently asked questions
What does "Validate" actually check?
It checks well-formedness — that every tag is properly opened, closed, and nested, and that the document follows valid XML syntax overall. It does not validate against a specific schema (XSD/DTD); it only confirms the XML itself is structurally correct.
What happens if I try to format invalid XML?
The tool reports an error instead of producing output. Some tools silently produce garbage when given malformed XML — this one explicitly detects a parse failure and tells you, rather than guessing at a "best effort" result.
Is my XML data uploaded anywhere?
No — parsing, formatting, and validation all happen locally in your browser using the native DOMParser API. Nothing you paste is ever sent to a server.
When should I minify XML instead of formatting it?
Minify when you need the smallest possible payload for transmission or storage — for example, embedding XML in a request body. Format (pretty-print) when you need to read or debug the structure by eye.
How do I check XML syntax online?
Use Validate first; malformed nesting, missing closing tags, and invalid attributes are reported before formatting or minifying.