XML Diff Tool

XML differencing in Altova DiffDog

XML Comparison and Editing:

  • Side by side comparison with highlighted differences
  • XML-aware comparison options
  • Merge differences in either direction
  • Syntax coloring
  • DTD/schema based entry helpers
  • Auto-completion of elements and attributes
  • Well-formedness and validation checking

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Comparing and Merging XML Files

The powerful XML differencing capabilities and XML editing features of DiffDog® 2015 draw on Altova’s legacy as creator of XMLSpy, the world’s leading XML development environment and the trusted choice of over 4 million users worldwide. With robust features such as well-formedness and validation checking, code completion, entry helpers, and more, DiffDog is a must-have differencing utility for Web and software developers working with XML.

The DiffDog XML file comparison mode includes all the same features that make text file differencing easy, such as file navigation aids and display customization options. In addition to those features, DiffDog includes functionality relevant to the unique nature of XML files. When you select two XML files to compare, DiffDog opens them side-by-side and indicates differences with colored highlighting and connecting lines. XML-conformant syntax coloring is supported, as well.

You have two options for displaying files: advanced text view and enhanced grid view. Advanced text view includes visual and navigation aids such as line numbers, book marks, and a source folding margin. Text view also allows you to reformat XML documents by indenting opening and closing element tags so that the layout reflects the structure of the document.

Enhanced grid view in Altova DiffDog

Enhanced Grid View

DiffDog also includes the enhanced grid view popularized by Altova XMLSpy. Grid view displays the hierarchical structure of an XML document through a set of nested containers. These can be easily expanded and collapsed to get a clear picture of the document's tree-like structure.

Grid view allows you to display an XML document in database/table view, which displays sequences of repeating elements in a tabular way similar to familiar database and spreadsheet applications.

Grid view includes an intuitive toolbar and right-click menu that allow you to insert and append elements, attributes, text, etc., add child elements and attributes, expand and collapse elements, and more.

Editing XML Files

All the DiffDog text file editing capabilities are supported for editing XML files in the comparison window, along with XML-specific editing features such as DTD/schema based entry helpers and auto-completion of elements and attributes.

These features help reduce the occurrence of errors. And, you can use the built-in well-formedness and validation engines to check files before saving.

XML-Aware Functionality

DiffDog is designed to adapt to the nature of XML documents with features relevant to XML syntax. For example, when comparing XML documents, you can specify if entities should be resolved, if namespace prefixes, whitespace, CDATA, processing instructions, comments, or the ordering of attributes/child elements should be ignored or not, how to visualize differences, and so on.

These XML-aware options are important for ensuring accurate comparison results. For instance, differences in namespace prefixes, order of XML attributes, or order of child elements can be irrelevant to XML processors, but prevent files from appearing equal in a simple text comparison.

Advanced XML find and replace is also supported, with options for restricting your search by elements, attributes, or text, and others.

XML comparison options in Altova DiffDog


"In no time at all, Altova DiffDog identified a minute discrepancy between our XML files that would have taken me hours to identify manually. Problem found equals problem solved – I'm a DiffDog fan for life!

– Michael Mullins, Applications Developer, West Virginia Division of Natural Resources