RSS 2.0 → Atom 1.0 Converter

RSS to Atom: why convert, and what changes

RSS (Really Simple Syndication) was born at UserLand and Netscape in 1999 and stabilised as RSS 2.0 in 2002 under the stewardship of Dave Winer and Harvard. Atom arrived later as RFC 4287 (2005), with the explicit goal of fixing the ambiguities RSS had accumulated through years of competing forks (0.90, 0.91, 0.92, 1.0, 2.0). Both formats publish the same conceptual data — a list of dated items pointing to a website — but Atom uses a proper XML namespace (http://www.w3.org/2005/Atom), mandates an <id> per entry, requires <updated> timestamps and supports relative URIs through xml:base. RSS keeps a flatter structure where <guid> is optional and dates are loosely typed (RFC 822 instead of RFC 3339).

Converting is useful in three scenarios. First, when a downstream parser only accepts Atom — common in newer reader SDKs that target RFC 4287 strictly. Second, when you aggregate several legacy RSS feeds into a unified Atom output that survives strict validators. Third, when you want to add WebSub (formerly PubSubHubbub) push notifications, which most reference implementations document against Atom.

Field mapping cheat sheet

• RSS <channel><title> → Atom <feed><title>
• RSS <link> → Atom <link rel="alternate" href="..."/> plus a self link
• RSS <item><guid> → Atom <entry><id> (must be an IRI)
• RSS <pubDate> (RFC 822) → Atom <published> / <updated> (RFC 3339)
• RSS <description> → Atom <summary> or <content type="html">

The 2024 feed revival

RSS and Atom are very much alive in 2024. Substack, Ghost and Beehiiv expose newsletter feeds; every Mastodon profile publishes one at /@user.rss; news aggregators like Feedly, Inoreader and NetNewsWire still rely on them; and the open podcast ecosystem effectively is RSS — Apple Podcasts mandates RSS 2.0 with the itunes: namespace and refuses Atom outright. Feeds are the canonical escape hatch from algorithmic timelines.

Validating the output

After conversion, run the result through the W3C Feed Validation Service (validator.w3.org/feed) or feedvalidator.org. Common errors flagged: missing <id> on entries, dates not in RFC 3339, relative URLs without an xml:base, and missing self link in the feed root.

FAQ

Are feeds still relevant in 2024? Very much so. The newsletter renaissance, Mastodon, the podcast ecosystem and a growing "small web" movement all run on RSS or Atom. Many static-site generators (Hugo, Eleventy, Jekyll) publish both by default.

Which is better — RSS or Atom? Atom has a stricter spec, better internationalisation (via xml:lang) and clean handling of binary content. RSS wins on tooling ubiquity, especially for podcasts where itunes: extensions are non-negotiable.

Can I submit an Atom feed to Apple Podcasts? No. Apple Podcasts requires RSS 2.0 with the itunes: namespace. Spotify, Google Podcasts and most podcatchers follow the same convention.

What about JSON Feed? JSON Feed (2017, by Brent Simmons and Manton Reece) is a JSON-native alternative supported by Inoreader, NetNewsWire and micro.blog. It coexists with RSS/Atom rather than replacing them — most modern generators publish all three.