scriptiii
100% Client-Side

well-formedness · not schema validation

XML formatter

Indent a document without losing what a token dumper would drop, and get the exact line when it is not well formed.

0 characters

Formatting happens in this tab. Configuration and SOAP payloads often carry internal hostnames, so nothing is uploaded.

Short answer: paste the document. If it is well formed you get the indented version and a count of elements, attributes, comments and depth; if not, you get the line the parser stopped on.

Well formed is not valid

These are two different checks and only the first one is possible without a schema. Well-formed means the document follows XML's syntax rules — one root, balanced tags, quoted attributes, escaped entities. Valid means it also matches a DTD or XSD. A document can be perfectly well formed and still be rejected by the service that expects a particular shape.

Why the formatter is order-preserving

A naive formatter rebuilds the document from a map of tag → value, which loses comments, reorders attributes and turns repeated child elements into an array that may not round-trip. Here the parse keeps the node order, so <!-- note --> stays where it was and a namespace prefix like soap: is not renamed.

Sending the result somewhere else? The JSON formatter and theYAML converter do the same job for other formats.

XML questions

Does this validate my XML against a schema?

No, and it will not pretend to. It checks well-formedness — balanced tags, quoted attributes, one root element — which is the layer that catches typos. DTD and XSD validation need the schema document and are a different job.

Is anything lost when I format it?

Comments, CDATA sections, processing instructions, namespace prefixes and attribute order are all preserved, because the parser runs in order-preserving mode. A formatter that drops a comment is a data-loss bug, not a formatting choice.

Why was my document rejected?

The usual causes are an unclosed tag, an attribute value without quotes, two root elements, or a bare ampersand. The message names the line and column, and the reason the parser gave.

What happens to the DOCTYPE?

A DOCTYPE is kept verbatim and placed back at the top of the output, but its internal subset is not parsed — entity declarations inside it are not expanded, and the page says so rather than quietly resolving them wrong.

Related tools

JSON formatterThe same job for JSON.YAML converterYAML to JSON and back.TOML converterTOML 1.0 with line numbers.All developer toolsThe rest of the suite.