XML Viewer Plus by Francesco De Stefano

XML Viewer Plus 2 — rewritten from scratch, now also on Firefox for Android.

Open any XML document and get a clean, fast, searchable view. Everything happens inside your browser: no data is collected or sent anywhere.

Opens XML automatically

• Detected by content type, so URLs without ".xml" work too (for example the OpenStreetMap API, SOAP services, sitemaps).
• text/xml, application/xml and every application/…+xml type: RSS, Atom, SOAP, KML, GPX, XSD, WSDL…
• Also XML files served as application/octet-stream or text/plain.
• Correct characters: ISO-8859-1, Windows-1252, Shift_JIS, UTF-16 and UTF-8 are decoded as the document declares.

Three views

• Tree — collapsible, colour-coded, fast even with tens of thousands of nodes (no line limit).
• Source — syntax-highlighted, pretty-printed or original, with line numbers.
• Feed — a clean reader view for RSS and Atom feeds.

Search

• Plain text, regular expressions, XPath and CSS selectors.
• XPath understands prefixes and default namespaces, and shows values for count(), sum() and other expressions.

Tools

• Node details: XPath, namespace, attributes; copy as XPath, XML, text or JSON.
• Copy or download as XML, minified XML or JSON.
• Clear error messages with line and column for malformed XML.
• Light, dark or automatic theme; adjustable text size.
• Right-click menu (desktop): view a selection, a link or the page as XML.
• Viewer page: paste XML, open or drop a file, open a URL.
• "View original page" shows a document the way the site styled it (e.g. XSLT).

Local files: to open local .xml files automatically, enable "Access local files on your computer" in the add-on's Permissions tab (required by Firefox since version 153).

Documentation and changelog: https://xml-viewer-plus.sourceforge.io/
Free and open source (MIT) — https://sourceforge.net/projects/xml-viewer-plus/