Validate OPML files and audit every feed before you switch readers.
An OPML file is an XML document used by RSS readers like Feedly, Inoreader, and NetNewsWire to export and share lists of feed subscriptions. An OPML validator checks that the file is well-formed XML, that the OPML root and required head and body elements are present, and that every feed outline has a valid xmlUrl, title, and type so it can be imported cleanly into a new reader.
Use the validator to spot malformed XML, missing OPML root or head and body elements, and feed outlines that ship without an xmlUrl. Then download a cleaned OPML file or copy the parsed feed list as JSON for automations and curation pipelines.
See the main AICurate productValidate an OPML file
Upload, paste, or fetch a public URL
Drop your .opml file here, or
Files stay on your device. We parse the XML in the browser.
Paste OPML XML
Best for quick checks, private files, or CORS-blocked URLs.
Results will appear here
Run the checker to see a section-by-section report.
Each validation run produces grouped results for XML structure, required head and body elements, feed counts, per feed errors, and warnings about missing optional metadata.
FAQ
Common questions about OPML validation
What is an OPML file?
OPML stands for Outline Processor Markup Language. It is an XML format used to share hierarchical lists, and the most common use today is exporting and importing RSS or Atom feed subscriptions between readers like Feedly, Inoreader, NetNewsWire, and The Old Reader. An OPML file contains a list of outline elements, where each feed-bearing outline has an xmlUrl attribute pointing at the feed.
How do I validate an OPML file?
Open this OPML validator, then upload the .opml file, paste the XML, or enter a URL. The tool parses the document in your browser, checks XML well-formedness, verifies the OPML root and required head and body elements, and lists every feed with its title and xmlUrl. Errors include line numbers so you can fix the file in a text editor and re-run the check.
What is the difference between OPML 1.0 and 2.0?
OPML 1.0 was the original spec with minimal required attributes on each outline. OPML 2.0 added a documented set of attributes for feed subscriptions, including xmlUrl, htmlUrl, type, version, and language, plus more head metadata. Most modern RSS readers export OPML 2.0. Files that declare an older version usually still import correctly, but missing attributes can lead to feeds being silently skipped.
Why is my OPML file not importing?
The most common reasons are malformed XML such as an unescaped ampersand, a missing OPML or head or body element, missing xmlUrl attributes on feed outlines, or invalid feed URLs. Some readers also reject files larger than a few megabytes or files with mixed encodings. This validator flags each of these so you can fix the file before retrying the import.
Is this OPML validator free and safe to use?
Yes. The tool is free, has no sign-up, and parses pasted or uploaded OPML entirely in your browser, so the contents of your subscription list never leave your device. The optional URL fetch path uses a small server-side proxy only to retrieve the file, then parses it client-side just like the paste path.
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Open toolBeyond Validation
Turn a clean OPML into a curated news hub
AICurate helps associations and publishers turn validated feed lists into branded AI-curated news hubs and digest workflows. Validate the file here, then import the cleaned OPML into the main product to start curating what matters.
Validator URL: https://www.aicurate.news/tools/free-opml-file-validator