How to merge XML documents
Start with the two XML documents and choose how their child elements should be combined. XML Merge Tool supports append, replace, and key-based child-element merging. Set identity and conflict policies when child elements need to be matched, then review the merged tree and categorized merge report before exporting XML.
- Open XML Merge Tool from this category.
- Provide the two XML documents you want to combine.
- Choose the merge strategy that fits the structure of those documents.
- Set the identity and conflict policies when the merge needs to match child elements.
- Preview the merged tree, then export the XML and its categorized merge report.
Which XML merge strategy should you use?
Append keeps child content from both documents in the merged result. Use it when the inputs contain separate entries that should stay together. Replace uses one document's matching content in place of the other document's content.
Key-based child-element merging matches repeated elements by identity. Set an identity field so XML Merge Tool can recognize a match, then choose the conflict policy for cases where both documents provide content for that item.
Input A: <items><item id="1"/></items>
Input B: <items><item id="2"/></items>
Append: <items><item id="1"/><item id="2"/></items>How key-based XML merging handles matches
The identity setting determines which child elements count as the same item. Choose a stable key that appears on the repeated elements you need to compare. The conflict policy determines how differences for a matched item are handled.
Review the tree preview after the strategy and policies are applied. The export includes the XML and a categorized merge report that records the merge decisions.
What XML Merge Tools do with different inputs
The result depends on the relationship between the two documents. Separate child elements can be appended, matching content can be replaced, or repeated child elements can be matched by identity. A key-based strategy needs an identity choice that distinguishes the records. If the key is missing or shared by unrelated records, inspect the preview and change the setup.
XML Merge Tools combine documents. They do not turn XML into JSON or run an XPath query. For those jobs, start in XML Tools, where the surrounding XML utilities are grouped by task.
Where XML merging comes up
Two XML configuration files may contain separate sections that need to appear in one document. Append keeps those child sections in the merged result for review.
A revised XML document may need to replace matching content in an older document. Replace sets that direction, and the preview shows the resulting tree before export.
Two XML documents may contain repeated records that represent the same items. A key-based strategy matches those records by identity, while the merge report records how conflicts were handled.
Frequently asked questions
How do I merge two XML documents?
Open XML Merge Tool, provide the two documents, choose append, replace, or a key-based child-element strategy, and preview the merged tree before exporting it.
What is the difference between append and replace in XML merging?
Append keeps child content from both documents in the result. Replace uses one document's matching content in place of the other document's content.
How does key-based XML merging choose matching elements?
Key-based merging uses the identity setting to recognize matching child elements. The conflict policy controls how differences for a matched item are handled.
Can I preview merged XML before exporting it?
Yes. XML Merge Tool previews the merged tree before export and provides a categorized merge report with the exported XML.