How to read Atom validation errors at w3.org?

If your Atom feed has errors, the Atom validator at w3.org will detect the errors and provide information to help you to resolve them as shown in this tutorial:

1. Go to Feed Validation Service at w3.org.

2. Click the "Validate by Direct Input" tab. You see a bigger input box for you to enter the Atom XML directly.

3. Enter the following invalid Atom XML:

<feed xmlns="http://www.w3.org/2005/Atom">
     <title>World News</title>
     <subtitle>This is an example of an RSS feed.</subtitle>
     <updated>2029-07-31 12:29:29</updated>
     <link rel="self" href="http://www.world-news.com/"/>
     <id>http://www.world-news.com/</id>
     <editor>
         <name>John Doe</name>
     </editor>
     <entry>
         <title>Breaking News!</title>
         <link rel="alternate" href="http://www.world-news.com/news/53f933c5395f"/>
         <id>http://www.world-news.com/news/53f933c5395f</id>
         <updated>2029-09-15T00:00:00Z</updated>
         <summary>Here is a breaking news that is still on going...</summary>
     </entry> 
</feed>

3. Click the "Check" button. You see the validation errors:

Sorry - This feed does not validate.

line 4, column 29: updated must be an RFC-3339 date-time: 2029-07-31 12:29:29 [help]
  <updated>2029-07-31 12:29:29</updated>
                             ^
line 7, column 1: Undefined feed element: editor [help]
  <editor>
 ^
line 16, column 1: Missing entry element: author [help]
  </entry> 
 ^
In addition, interoperability with the widest range of feed readers could be improved by implementing the following recommendations.
line 5, column 53: Self reference doesn't match document location [help]
  <link rel="self" href="http://www.world-news.com/"/>
                                                     ^
line 14, column 31: Implausible date: 2029-09-15T00:00:00Z [help]
    <updated>2029-09-15T00:00:00Z</updated>

Click on "[help]" for more information on each error. Then go back to fix them.

The picture below shows you Atom validation errors at w3.org:

⇒ View Atom Feeds with IE (Internet Explorer)

⇐ Atom Online Validator at w3.org

⇑ Using Atom Tools

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