10 min read · Try XML Formatter
XML is still infrastructure
RSS/Atom feeds, SAML metadata, SOAP WSDL, Android resources, and legacy enterprise buses rely on XML schemas. JSON won the greenfield API race, but XML maintenance continues for years.
Namespaces and prefixes
Default namespaces change XPath results. Keep prefixes stable across files in the same integration so diffs stay readable and queries do not silently break.
Well-formed vs valid
Well-formed XML parses; valid XML also conforms to XSD or Relax NG. CI should run schema validation on config that can take production offline.
Pretty-print for humans
Minified XML saves bytes; pretty XML saves incident time. Store pretty in git when humans review changes, minify only at deploy if bandwidth requires it.
Security
Billion laughs and external entity attacks are mitigated by disabling dangerous parser features in server code. Browser formatters are for inspection, not processing untrusted uploads at scale.
This article is part of the DevToolsHub learning guides—original writing meant to complement our free tools, not replace official documentation from vendors or standards bodies.