What Happens If Your Atom Feed Fails the Validation? - RSS FAQs - Atom Feed Introduction and File Generation

If your Atom feed file fails the w3.org validator, you will get an error message explaining where the error is in your feed file. The tutorial exercise below shows you a good example.

Try to validate the following Atom feed file:

<?xml version="1.0" encoding="utf-8"?>
<feed xmlns="http://www.w3.org/2005/Atom">
 <title>Webmaster FYI Center</title>
 <subtitle>A place to find information for Webmasters
 </subtitle>
 <link href="http://dev.fyicenter.com/atom.xml"/>
 <id>http://dev.fyicenter.com/</id>
 <updated>2005-07-13T18:30:02Z</updated>
 <author>
  <name>FYIcenter.com</name>
  <email>noreply@fyicenter.com</email>
 </author>
 <entry>
  <title>Webmaster FAQ Collection</title>
  <link href="http://dev.fyicenter.com/faq/"/>
  <id>http://dev.fyicenter.com/faq/</id>
  <updated>2005-07-13T18:30:02Z</updated>
  <summary>A massive collection of FAQs for Webmasters.
  </summary>
 </entry>
</feed>

You will get the following error message:

line 2, column 3: Missing atom:link with rel="self"

   <feed xmlns="http://www.w3.org/2005/Atom">

Why? Because the feed link element is missing the rel="self" attribute.