What is XML?
XML (Extensible Markup Language) is the structured data format underlying RSS feeds. Every podcast feed is an XML document that organizes show and episode data in a hierarchical, machine-readable format that apps can parse and display.
XML Basics for Podcasters
XML uses tags to structure data:
<?xml version="1.0" encoding="UTF-8"?>
<rss version="2.0">
<channel>
<title>My Podcast</title>
<description>A show about things</description>
<item>
<title>Episode 1</title>
<enclosure url="https://..." type="audio/mpeg" length="12345" />
</item>
</channel>
</rss>
Key concepts:
- Elements: Data wrapped in tags like
<title>...</title> - Attributes: Properties within tags like
url="https://..." - Hierarchy: Elements nested inside other elements
- Declaration:
<?xml version="1.0"?>declares the document type
XML Namespaces
Namespaces extend XML with additional tag vocabularies:
<rss version="2.0"
xmlns:itunes="http://www.itunes.com/dtds/podcast-1.0.dtd"
xmlns:podcast="https://podcastindex.org/namespace/1.0">
This enables:
- iTunes tags:
<itunes:author>,<itunes:duration> - Podcast 2.0:
<podcast:chapters>,<podcast:transcript>
Common XML Pitfalls
| Issue | Problem | Solution |
|---|---|---|
Unescaped & |
Invalid XML | Use & |
Unescaped < |
Breaks parsing | Use < |
| Wrong encoding | Garbled characters | Ensure UTF-8 |
| Unclosed tags | Parse failure | Always close tags |
| Invalid characters | Feed rejection | Sanitize input |
Character escaping:
<!-- Wrong -->
<title>Tom & Jerry</title>
<!-- Correct -->
<title>Tom & Jerry</title>
Why It Matters
While you'll rarely edit XML directly, understanding its basics helps you troubleshoot feed problems and interpret validation errors.
Why XML knowledge helps:
-
Debugging feed issues: When a directory reports "invalid XML," knowing the basics helps you identify the problem.
-
Understanding error messages: Validation errors reference XML concepts like elements, attributes, and encoding.
-
Reading raw feeds: Sometimes viewing your feed's source XML reveals issues not visible in dashboard interfaces.
-
Evaluating features: Understanding XML structure helps you grasp what Podcast 2.0 features do and why they matter.
Common scenarios requiring XML awareness:
| Scenario | Why XML Matters |
|---|---|
| Episode description contains HTML | Must be properly encoded |
| Show title has special characters | Escaping prevents parse errors |
| Directory rejects feed | XML validation error needs fixing |
| Migrating hosts | Understanding feed structure helps verify |
The abstraction layer: Good podcast hosting platforms handle XML generation automatically, escaping special characters and ensuring validity. But when something goes wrong, knowing what's under the hood helps you diagnose and communicate issues.