XML parsererror: what it means and how to fix invalid XML

TL;DR: Fix XML validity first, then convert XML to JSON locally (no upload).

When DOMParser can’t parse your XML, browsers often insert a <parsererror> element. The fix is usually a small syntax mistake—once you know what to look for.

Common causes of invalid XML

  • Unclosed tags: missing </tag> or wrong nesting order.
  • Invalid characters: unescaped &, <, or control chars in text.
  • Multiple root elements: XML must have exactly one root element.
  • Namespace issues: prefixes used without proper xmlns declarations.

Fast debugging steps

  1. Search for raw & inside text and escape as &amp;.
  2. Check the last lines: many errors happen near the end (missing closing tags).
  3. Ensure there is only one root element.
  4. If namespaces exist, verify that prefixes are declared on the root or relevant nodes.

Conversion tip: validate before you serialize

Converters can only create JSON if the XML tree is valid. Fix syntax first, then convert. If output is surprising (arrays vs objects, attributes), review the mapping rules.

Practical checklist (fast)

If you’re stuck, use this quick checklist to narrow the problem before you try “random fixes”. Start by validating the input format (syntax first), then confirm shape expectations (array vs object, headers vs rows). Convert a small sample, inspect the output, and only then export the full result.

  • Validate: confirm the input is strict JSON/XML/CSV (no stray characters).
  • Confirm shape: arrays vs objects; headers vs row lengths; repeated tags vs arrays.
  • Test a sample: first 20–50 rows/items are enough to detect parsing issues.
  • Export: copy/download the output and re-check it in the consumer (script/spreadsheet/API).

This workflow is privacy-first by design: All processing happens locally in your browser. Files are never uploaded.

FAQ

Why is the error message different across browsers? DOMParser error formatting varies. Focus on the location and the underlying cause (unescaped char, nesting, namespaces).

Is it safe to debug XML online? Avoid uploads for private feeds—local parsing keeps data on-device.

Trust note: All processing happens locally in your browser. Files are never uploaded.

Next steps
Privacy & Security
All processing happens locally in your browser. Files are never uploaded.