XML tools

Compare XML in Notepad++ Without Hiding Meaningful Changes

Use Notepad++ with ComparePlus to review two XML files, distinguish line differences from XML structure, and preserve meaningful whitespace and source files.

By Uddhav Gopani, FounderPublished 27 September 2026Updated 29 September 2026

Use Notepad++ with a comparison plugin

To compare two XML files in Notepad++, use a supported comparison plugin such as ComparePlus. Notepad++ is a separate editor from the basic Windows Notepad application. A plugin workflow described for Notepad++ will not appear in Windows Notepad's menus.

The ComparePlus project documents its side-by-side comparison and installation through Notepad++'s Plugins Admin. Check the plugin's compatibility information for your installed editor version before installing it. Use the official plugin listing or project source instead of an unrelated download mirror.

Open the two source versions and compare them

Save or copy the two versions to distinct files with clear names, such as settings-before.xml and settings-after.xml. Open both in Notepad++. Confirm which tab contains the earlier version and which contains the proposed change before starting the comparison.

After installing the compatible plugin and restarting the editor if requested, use its comparison command from the Plugins menu. Review the two views and the plugin's current comparison settings. Menu wording and available options can vary by plugin version, so use the project's documentation for the installed release.

Do not save a reformatted copy over an original merely to make the display easier to read. Keep the original files available throughout the review. If you compare unsaved editor buffers, record that fact; the visible contents can differ from the last saved files on disk.

Practice with a known one-line change

<settings>
  <retry count="2"/>
</settings>

<settings>
  <retry count="4"/>
</settings>

The review should show the retry count changing from 2 to 4. Next add a new sibling element to the revised file and verify that its inserted line is visible. These small checks help confirm that you selected the intended pair of buffers and understand which side is treated as revised.

Keep comparison settings appropriate to XML

A line comparison can show changes in indentation, attribute ordering and line endings even when an application reads equivalent XML values. Those are legitimate source changes. Decide whether the review concerns the exact source or a parsed representation before suppressing categories of differences.

Ignoring whitespace globally can hide meaningful text changes. In a paragraph containing an inline element, a space after the closing inline tag may separate two words. Removing or ignoring that space can change the rendered sentence while making the diff appear quieter.

Likewise, sorting lines is not an XML-aware way to match records. It can separate opening tags from their children or hide sequence changes that the consumer depends on. If a collection is unordered by contract, use a comparison that matches complete records by a verified unique key.

Use a parsed comparison for a different question

The local XML comparison tool can provide a second view of a small pair. Its ordered parsed-tree policy ignores attribute order and namespace-prefix spelling while retaining parsed text whitespace and child order. That policy differs from a line-by-line editor comparison.

Neither view alone validates the XML against an XSD or proves application compatibility. A changed schema reference, a renamed field or a moved element still needs testing with the actual consumer. Keep a parser or schema-validation error separate from an ordinary difference report.

Finish with a reproducible review record

Record the two file versions, the plugin version and any ignore settings used. Review each substantive change before manually merging it. A highlighted line indicates a difference, not an instruction to accept the revised value.

The Notepad++ plugin documentation explains the editor's plugin management. If installation is unavailable on a managed computer, follow the organization's supported editor workflow or use the browser comparison for a small permitted sample; do not change system permissions merely to force a plugin installation.