RSS (Really Simple Syndication) and Atom are both web feed formats used for syndicating frequently updated content such as blog posts, news articles, and podcasts. Here are the main differences between them:
Content payloads
- RSS only provides escaped HTML or plain text content.
- Atom can provide various types of content (HTML, text, media, etc.) within the same payload.
Internationalization
- RSS provides internationalization at the feed level.
- Atom provides internationalization at every individual element level, allowing better support for international characters.
Markdown support
- RSS does not support custom XML markup, so text formatting is often lost.
- Atom supports preserving formatting like markdown.
Entry identification
- RSS feeds lack unique identifiers for entries, making it harder to track updates across different feed URLs.
- Atom entries have globally unique IDs, allowing seamless merging of entries from different feed URLs.
Date handling
- RSS initially lacked date information until version 2.0, and its date formatting is ambiguous.
- Atom has always had clear published and updated date elements using the RFC 3339 format.
Specification quality
- The RSS specification has ambiguities that lead to inconsistent interpretations.
- Atom has a stricter and more well-defined specification, guiding authors to create valid feeds.
While RSS is more widely adopted, especially for podcasting, Atom is considered a technically superior format with better features for content publishing and syndication. Most feed readers support both formats.