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Bulk up to 100 • Atom/RSS syntax • Sitemap vs feed detection

RSS Validator

Check the syntax of Atom or RSS feeds. If you paste a sitemap.xml, we’ll flag it with W3C-style errors (e.g., Undefined root element: urlset).

Paste up to 100 feed URLs (or site URLs) (one per line)
Tries HTML <link rel="alternate"> and common paths.
Tip: sitemap.xml is NOT an RSS feed. If you validate a sitemap as a feed, it will “not validate” by design.

Results

Host Validation HTTP Hops Time Issues
Run a check to see results here.
If you see “Undefined root element: urlset”, you validated a sitemap as a feed.

Quick interpretation

RSS/Atom requires a valid root element and strict XML syntax.

  • OK feed detected (RSS/Atom), basic parse successful
  • Warning parse warnings, missing title/items, autodiscovery, generic content-type
  • Error fetch errors, redirect loops, HTTP 4xx/5xx
Feed syntax

RSS Validator: W3C-style feed validation for Atom and RSS

This tool validates RSS and Atom feeds and highlights the same class of problems you’ll see in feed validators: wrong root elements, XML parse errors, and compatibility recommendations. It also detects the common mistake of pasting a sitemap.xml into a feed validator (root urlset).

Common “does not validate” reasons

  • You used a sitemap URL (urlset) instead of a feed (rss/feed).
  • Broken XML (invalid characters, unescaped &, truncated output).
  • HTML pages served as XML (WAF, login pages, soft 404 pages).

FAQ

Why does my sitemap.xml “not validate” as RSS?

Because a sitemap is not a feed. RSS/Atom expects root <rss> or <feed>, but sitemaps use <urlset> or <sitemapindex>. That’s why you see W3C-style messages like Undefined root element: urlset.

What feed types do you detect?

The validator detects RSS (root rss) and Atom (root feed). If the root is something else, it’s flagged as “unknown feed root”.

What does “application/xml is not specific enough” mean?

It’s a compatibility recommendation: some feed readers prefer a specific MIME type like application/rss+xml or application/atom+xml. application/xml often still works, but it’s a weaker signal.

Should I enable auto-discovery?

Enable it if you paste a site URL (homepage) instead of a direct feed URL. The tool tries HTML autodiscovery via <link rel="alternate"> and also checks common paths like /feed, /rss.xml, /atom.xml.

Why do I get “not XML” or “XML parse error”?

Common causes: the URL returns HTML (login page, WAF block, consent page), the feed is truncated, or it contains invalid characters / unescaped symbols like &. The validator shows a readable parse message with line/column when possible.

My feed has 0 items — is it broken?

Not always, but it’s usually a warning. Many readers expect at least one <item> (RSS) or <entry> (Atom). If your feed is new, publish at least one post/item.

Do you fetch the full feed or a sample?

This bulk validator fetches a sample (up to the tool’s byte limit) for speed and safety. If a huge feed is truncated, you may see warnings. For full-source inspection, use a dedicated “show full XML” tool/page.

Why does it show “warnings” even when HTTP is 200?

HTTP 200 only means the server responded successfully. A feed can still be invalid XML, be a sitemap, miss required elements, use a generic content-type, or contain no entries — those are validation-level warnings.