RSSを66のSNSへ: Facebook、Instagram、X、LinkedIn、Telegramほか ブログ アフィリエイト お問い合わせ
ログイン 無料で始める

XML

XML is the underlying markup format RSS feeds are built on, and understanding its basic rules — well-formed tags, namespace declarations, character encoding — helps explain why some feeds behave predictably in auto-posting tools while others produce missing images, broken characters, or dropped items. This tag covers the XML-level mechanics behind RSS and Atom feeds. Two articles go further into the detail: a roundup of feed validators and debugging tools for finding what is malformed, and an explanation of the namespaces you will meet in real feeds, including media:content and the iTunes podcast extensions. Between them they cover most of the reasons an item arrives without its image or with the wrong characters. You do not need to write XML to run a feed, but knowing what a validator is complaining about saves a lot of guessing.
Missing atom:link rel=”self”: Fixing the Feed Warning
Updated: 2026-10-02

Short answer: The warning means your RSS feed does not state its own address. Declare the Atom namespace on the <rss> ele...

続きを読む »
RSS Feed Content-Type: application/rss+xml or text/xml?
Updated: 2026-10-02

Short answer: Serve an RSS 2.0 feed as application/rss+xml; charset=utf-8 and an Atom feed as application/atom+xml; charset=utf...

続きを読む »
CDATA and HTML in RSS Descriptions: Escaping Done Right
Updated: 2026-10-01

Short answer: HTML inside an RSS description or content:encoded element must be either entity-escaped (&lt;p&gt;) or wr...

続きを読む »
RSS Date Formats Explained: RFC 822 pubDate Errors and Fixes
Updated: 2026-10-01

Short answer: In RSS 2.0, pubDate and lastBuildDate must use the RFC 822 date format, for example Tue, 29 Sep 2026 08:00:00 +00...

続きを読む »
How to Write an RSS Feed by Hand: A Minimal Valid Example
Updated: 2026-10-01

Short answer: A minimal valid RSS 2.0 feed is a UTF-8 XML file with an rss root element, one channel containing a title, link a...

続きを読む »
Styling Your RSS Feed for Browsers: XSLT, CSS and Alternatives
Updated: 2026-09-30

Short answer: When someone clicks your RSS feed link, most browsers show raw XML, which looks broken to non-technical visitors....

続きを読む »
RSS Feed XML Declaration Error: Fixing Whitespace Before XML
Updated: 2026-09-29

Short answer: The error "XML declaration allowed only at the start of the document" means something is printed before the <?...

続きを読む »
Top 10 RSS Feed Validators and Debugging Tools for Fixing Auto-Posting Issues
Updated: 2026-09-27

A surprising number of auto-posting problems — missing images, dropped items, garbled titles — trace back to a feed that's tech...

続きを読む »
RSS Namespaces Explained: What media:content, itunes:, and dc: Tags Mean for Auto-Posting
Updated: 2026-09-29

If you've ever opened your own RSS feed in a text editor and seen tags like media:content, itunes:image, or dc:creator mixed in...

続きを読む »

私たちのチームが作るほかのツール

PostRSSを手がけるInternet Solutionsが開発。どの製品も、それぞれの形で時間を節約します。