Overview
Introduction
Before writing a parser or schema against an unfamiliar XML document, it helps to know its full tag vocabulary at a glance.
This tool lists every distinct tag name once.
What Is XML Key Extractor?
An extraction tool that walks the parsed document and collects every unique element tag name.
Results are deduplicated and kept in first-seen order, matching the order tags first appear in the source document.
How XML Key Extractor Works
The document is parsed and walked once.
Each element's tag name is added to a list only the first time it's seen, producing a deduplicated vocabulary in document order.
When To Use XML Key Extractor
Use it to quickly see every distinct tag name an unfamiliar document uses.
It's a natural first step before writing a parser or XPath query against that document.
Often used alongside XML Key Finder, XML Value Extractor and XML Key Replacer.
Features
Advantages
- Deduplicated, so the list stays short even for documents with many repeated elements.
- Runs entirely client-side.
- First-seen ordering makes the list easy to scan alongside the document itself.
Limitations
- Doesn't show how many times each tag appears, use Find XML Keys for occurrence counts.
- Doesn't show where in the document's structure each tag appears, use the XML Visualizer for that.
Examples
Best Practices & Notes
Best Practices
- Run this first on an unfamiliar document, before writing a parser or XPath query against it.
- Cross-check the list against your schema or expected field names for typos or unexpected additions.
- Re-run after a data migration to confirm no unexpected tag names were introduced.
Developer Notes
Deduplication uses a simple `includes` check against a growing array during a single tree walk, adequate for the tag-count range these documents realistically have.
XML Key Extractor Use Cases
- Getting a document's full tag vocabulary before writing a parser
- Confirming a document doesn't use an unexpected tag name
- Comparing two documents' tag vocabularies for schema drift
Common Mistakes
- Expecting occurrence counts, this list is deduplicated; use Find XML Keys or XML Statistics for frequency.
- Assuming tag order in the list reflects nesting depth, it reflects first-seen document order instead.
Tips
- Pair with XML Statistics if you also want to know how often each tag appears.
- Check the FAQ above if the output doesn't look like what you expected.