XML (eXtensible Markup Language), defined by the W3C XML 1.0 specification, remains the data format of choice for SOAP web services, RSS/Atom feeds, SVG graphics, Android layout files, Maven POM files, and countless enterprise integration protocols. Raw XML from APIs and log files is often minified or improperly indented, making it unreadable. Validating well-formedness — proper tag nesting, attribute quoting, and a single root element — before sending XML in an API request catches integration errors that would otherwise surface as cryptic HTTP 400 responses.
The formatter parses XML using the browser's DOMParser API with the "text/xml" MIME type. DOMParser implements the W3C DOM Level 3 Core specification and returns a Document object or a parseerror document if the input is not well-formed. Syntax errors from DOMParser include a message and the line number of the first invalid token.
Formatting serializes the parsed DOM back to a string using a recursive tree-walking function that applies indentation proportional to the element nesting depth. Text nodes with only whitespace are discarded during serialization to prevent double-indentation artifacts from pre-formatted input. Attribute values are preserved verbatim.
Minification serializes the DOM with no indentation and removes all non-significant whitespace between elements. Text content of mixed-content elements (elements that contain both text and child elements) is preserved. The output is a single-line string suitable for embedding in code or API payloads.
A backend developer debugging a SOAP integration pastes a minified request body to format it for inspection before comparing it against the WSDL spec.
A developer working with Android layouts formats an auto-generated XML file from a build tool to make it readable before editing.
A data engineer validates that an XML export from a legacy system is well-formed before importing it into a pipeline that would fail silently on malformed input.
A developer formats an RSS feed response to verify the channel and item elements conform to the expected structure for a feed reader integration.
Paste XML in the input panel
Click Format to beautify or Minify to compress
Validation errors are shown with line numbers
Copy the formatted output with one click
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