The W3C has a very nice Feed Validation Service[1], but it only looks at the feed itself, not at the linked pages. And a lot of the problems that it finds are issues in the body content which can mask more serious errors.

So I write an RSS/Atom Feed Analyzer[2] that checks for things like headers, consistent links and backlinks.

One of the (potentially) more controvesial things it recommends is using the content type "text/xml". The normal recommendation causes the "Save As" dialog popup in some browsers, which is IMHO a horrible user experience.

Anyhow, give it a try and let me know what you think! RSS.Style has a list of high-profile bloggers' feeds[3] that you can try. And feel better about having problems in your own feed!

Source (TypeScript) is available[4] (MIT license). It is running as a function on Cloudflare Pages. It is just something that I hacked together and grew over time: don't be judgemental!

PS: And use https://www.rss.style/ to make you feeds look nicer in a browser!

[1] https://validator.w3.org/feed/

[2] https://www.rss.style/feed-analyzer.html

[3] https://www.rss.style/#examples

[4] https://github.com/fileformat/rss.style/blob/main/functions/...