Google Feed Invalid XML (broken product feed)

The issue

A single XML error can stop feed processing entirely. Common causes include unescaped & characters, tag mismatch, hidden encoding bytes (BOM), or missing the xmlns:g namespace when using g: attributes.

• Well-formed XML is required before any Merchant checks.
• Namespace matters: g: attributes need xmlns:g.
• Unescaped characters inside text nodes break parsing.

Broken example

This example fails because it uses g: attributes without declaring the namespace, and includes a bare ampersand inside <g:title>.

<?xml version="1.0" encoding="UTF-8"?>
<rss version="2.0">
  <channel>
    <title>My Store</title>
    <item>
      <g:id>SKU-1001</g:id>
      <g:title>Salt & Pepper Shakers</g:title>
      <g:price>19.99 USD</g:price>
    </item>
  </channel>
</rss>

The fix

Declare the Google namespace once on the root element and escape characters like & as & (unless the text is inside CDATA).

<?xml version="1.0" encoding="UTF-8"?>
<rss version="2.0" xmlns:g="http://base.google.com/ns/1.0">
  <channel>
    <title>My Store</title>
    <item>
      <g:id>SKU-1001</g:id>
      <g:title>Salt &amp; Pepper Shakers</g:title>
      <g:price>19.99 USD</g:price>
    </item>
  </channel>
</rss>