XML Namespace Resolver
Expand every prefix to its URI, list all declared namespaces, and flag unused or undeclared ones.
What is Namespace Resolver?
A namespace report. Prefixes are local to the element that declares them, which is why a document can use `ns:` for two different URIs on two different branches — and why 'add the namespace' advice fails without saying which one.
How it works
Every element is walked carrying the namespaces in scope, so each declaration is reported with its URI, its line, the element path that declares it, and whether it is the default namespace. Attributes are resolved separately and correctly: an unprefixed attribute is in no namespace even when a default namespace is declared, a rule most libraries get wrong in one direction or the other.
- Paste the document. Drop in XML, a schema, a feed or an XPath expression. Everything is parsed in the page: no upload, no server round trip, and the tools keep working with the network switched off.
- Set the options that match your document. Indent unit, whether to keep comments, which dialect, which output method. The defaults are the safe ones — nothing that changes meaning is enabled for you.
- Read the result, then copy or download it. Results appear as you type, copy straight to the clipboard, and download with a sensible filename (.xml, .xsd, .csv). Reset returns every field to its default.
Examples
A minified document from an API response
Paste one line of XML and the Formatter indents it, wraps long start tags one attribute per line and normalises empty elements — without touching text inside mixed content.
An XPath that works in Chrome and not in your servlet
The XPath Tester evaluates against a real tree and reports the axis or function it cannot support, instead of returning zero nodes and letting you guess why.
A document that will not parse
The Validator gives line and column for every mismatched tag, stray ampersand and duplicate attribute, with the reason in words: which open element was expected, which was found.
A schema that only half matches your data
The XSD Validator marks each violation with the path of the offending node, and the Schema Generator goes the other way — inferring a starting-point XSD from real documents.
Common mistakes
Assuming a pretty-printer cannot change meaning
Whitespace between elements is often insignificant, but inside mixed content it is not: `<p>Hello <b>world</b></p>` must stay on one line. Formatting here re-indents element-only content and leaves mixed content alone.
Treating a validation pass as proof of interoperability
The DTD and XSD validators implement honest subsets. A document reported valid here can still be rejected by a full validator that understands identity constraints, substitution groups or XSD 1.1 assertions — each page lists what it does not cover.
Reading the whole document because the parser did
A DOCTYPE is not inert. If your parser resolves external entities, pasting an untrusted document is enough to read a file or call an internal URL. The XXE Risk Checker shows what a document asks for; the fix is in the parser configuration.
Forgetting that attributes and elements are not interchangeable
`<id>1</id>` and `id="1"` mean different things to every schema and every XPath. When converting to CSV or YAML the distinction is preserved (`@id`), because flattening it away is the change that costs an afternoon later.
Frequently asked questions
Why is my attribute not in the default namespace?
Because the XML namespace specification says so: a default namespace declaration applies to elements, never to attributes. An unprefixed attribute has no namespace at all. This is the single most common source of 'the schema says the attribute should be there' bugs.
What does an undeclared prefix mean?
The document is not namespace-well-formed: no ancestor declares that prefix, so a conforming parser must reject it. In practice, lenient parsers drop the prefix and hand you an element with a different name than you expect — which is why it is reported as an error rather than a warning.
Is a namespace URI fetched?
Never. A namespace name is an identifier, not a location: `http://example.com/ns` does not have to resolve to anything, and parsers must not fetch it. This tool only reads what the document declares.