RSS (Really Simple Syndication) is an XML-based web feed format that allows users and applications to subscribe to content updates from websites in a standardized, machine-readable way. When a website publishes an RSS feed, subscribers automatically receive new content — such as blog posts, news headlines, podcast episodes, or video updates — without having to manually visit the site.
RSS is one of the oldest and most widely adopted standards on the web. It powers podcast distribution, news aggregation, and content syndication across millions of websites. Despite the rise of social media, RSS remains a foundational technology for the open web.
The RSS workflow involves three components:
https://example.com/feed.xml). It is updated whenever new content is published.This publish-subscribe model means content consumers get updates delivered to them, rather than having to poll individual websites. It's efficient, privacy-respecting (no tracking or algorithmic filtering), and entirely under the user's control.
RSS has a complex history involving competing visions, forked specifications, and a format war that ultimately led to the creation of the Atom syndication format.
| Version | Date | Developer | Notes |
|---|---|---|---|
| RSS 0.90 | March 1999 | Netscape (Guha) | Original format, based on RDF. Created for the My Netscape portal. |
| RSS 0.91 | July 1999 | Netscape | Simplified version that removed RDF. Adopted by UserLand Software. |
| RSS 1.0 | December 2000 | RSS-DEV Working Group | Returned to RDF. Used XML namespaces. Not a direct successor to 0.91. |
| RSS 0.92 | December 2000 | Dave Winer / UserLand | Evolved from 0.91, added optional elements including <enclosure>. |
| RSS 2.0 | September 2002 | Dave Winer | Final evolution of the 0.9x line. Frozen specification. |
| RSS 2.0.1 | July 2003 | Harvard / RSS Advisory Board | Spec transferred to Harvard under Creative Commons license. |
The naming conflict between RSS 1.0 (RDF-based) and RSS 2.0 (non-RDF) caused significant confusion. These are effectively two different formats that share the same acronym. RSS 2.0 became the dominant version, and the specification was frozen — meaning no new features will be added, only clarifications.
An RSS 2.0 document is a well-formed XML file with a specific structure. Here is the complete anatomy of an RSS feed:
<?xml version="1.0" encoding="UTF-8"?>
<rss version="2.0"
xmlns:atom="http://www.w3.org/2005/Atom">
<channel>
<title>Example News</title>
<link>https://www.example.com</link>
<description>Latest news and articles from Example</description>
<language>en-us</language>
<lastBuildDate>Tue, 04 Mar 2026 10:00:00 GMT</lastBuildDate>
<atom:link href="https://www.example.com/feed.xml"
rel="self" type="application/rss+xml"/>
<item>
<title>Understanding XML Namespaces</title>
<link>https://www.example.com/xml-namespaces</link>
<description>A deep dive into how XML namespaces work
and why they matter for document interchange.</description>
<pubDate>Tue, 04 Mar 2026 08:30:00 GMT</pubDate>
<guid isPermaLink="true">https://www.example.com/xml-namespaces</guid>
<category>XML</category>
</item>
<item>
<title>Getting Started with XSLT</title>
<link>https://www.example.com/xslt-guide</link>
<description>Learn how to transform XML documents into
HTML, text, and other formats using XSLT.</description>
<pubDate>Mon, 03 Mar 2026 14:00:00 GMT</pubDate>
<guid isPermaLink="true">https://www.example.com/xslt-guide</guid>
<category>XSLT</category>
</item>
</channel>
</rss>Every RSS 2.0 feed must contain a <channel> element with these three required child elements:
| Element | Description | Example |
|---|---|---|
<title> | The name of the feed/channel | <title>Tech Daily</title> |
<link> | URL to the corresponding website | <link>https://techdaily.com</link> |
<description> | A phrase or sentence describing the channel | <description>Daily technology news</description> |
The following elements are optional but widely used:
| Element | Description |
|---|---|
<language> | The language the feed is written in (e.g., en-us, fr) |
<copyright> | Copyright notice for the feed content |
<managingEditor> | Email address of the editorial contact |
<webMaster> | Email address of the technical contact |
<pubDate> | Publication date of the feed content (RFC 822 format) |
<lastBuildDate> | The last time the feed content was updated |
<category> | One or more categories the feed belongs to |
<generator> | The software used to generate the feed |
<docs> | URL pointing to the RSS specification documentation |
<ttl> | Time to live — minutes a feed can be cached before refreshing |
<image> | An image (logo) associated with the feed |
<cloud> | Enables publish-subscribe (rssCloud) notifications |
<skipHours> | Hours when aggregators can skip checking the feed |
<skipDays> | Days when aggregators can skip checking the feed |
Each <item> in the feed represents a piece of content. At minimum, an item must contain either a <title> or a <description> (or both). All other elements are optional.
| Element | Description |
|---|---|
<title> | The headline of the item |
<link> | URL to the full content |
<description> | Synopsis or full text of the item (supports HTML) |
<author> | Email address of the item's author |
<category> | One or more categories the item belongs to |
<comments> | URL to a comments page for the item |
<enclosure> | Attached media file (URL, length in bytes, MIME type) |
<guid> | A globally unique identifier for the item |
<pubDate> | When the item was published (RFC 822 format) |
<source> | The originating RSS feed if the item was aggregated |
The <enclosure> element is particularly important because it enabled podcasting. It attaches a media file to an item using three required attributes:
<enclosure
url="https://example.com/episode-42.mp3"
length="24986239"
type="audio/mpeg" />The url attribute points to the media file, length specifies the file size in bytes, and type is the MIME type. This simple mechanism, introduced in RSS 0.92, became the foundation for the entire podcast industry.
RSS is the backbone of podcast distribution. When you subscribe to a podcast in Apple Podcasts, Spotify, or any podcast app, you're subscribing to an RSS feed that contains <enclosure> elements pointing to audio files.
Podcast feeds extend RSS 2.0 with additional namespaces, most notably the iTunes namespace:
<?xml version="1.0" encoding="UTF-8"?>
<rss version="2.0"
xmlns:itunes="http://www.itunes.com/dtds/podcast-1.0.dtd"
xmlns:atom="http://www.w3.org/2005/Atom"
xmlns:podcast="https://podcastindex.org/namespace/1.0">
<channel>
<title>The XML Podcast</title>
<link>https://example.com/podcast</link>
<description>Weekly discussions about XML technologies</description>
<language>en-us</language>
<itunes:author>XML Files</itunes:author>
<itunes:category text="Technology" />
<itunes:image href="https://example.com/podcast-artwork.jpg" />
<itunes:explicit>false</itunes:explicit>
<atom:link href="https://example.com/podcast/feed.xml"
rel="self" type="application/rss+xml" />
<item>
<title>Episode 42: The Future of RSS</title>
<description>We discuss why RSS remains relevant
in the age of social media algorithms.</description>
<enclosure url="https://example.com/episodes/ep42.mp3"
length="24986239" type="audio/mpeg" />
<guid isPermaLink="false">ep-42-future-of-rss</guid>
<pubDate>Mon, 03 Mar 2026 09:00:00 GMT</pubDate>
<itunes:duration>00:52:14</itunes:duration>
<itunes:episode>42</itunes:episode>
</item>
</channel>
</rss>The Apple Podcasts specification requires the iTunes namespace (xmlns:itunes) and supports elements like:
<itunes:author> — The podcast creator's name<itunes:category> — The podcast category (e.g., Technology, Business)<itunes:image> — Podcast artwork (minimum 1400x1400, recommended 3000x3000)<itunes:explicit> — Whether the podcast contains explicit content<itunes:duration> — Episode length in HH:MM:SS format<itunes:episode> — Episode number<itunes:season> — Season number<itunes:type> — Either episodic or serialThe newer Podcasting 2.0 namespace (xmlns:podcast) adds modern features like transcripts, chapters, funding links, and value-for-value payments.
Atom (RFC 4287) is an alternative syndication format that was developed starting in 2003 to address limitations in RSS. Here's how they compare:
| Feature | RSS 2.0 | Atom 1.0 |
|---|---|---|
| Standard | Frozen spec (Harvard/RSS Advisory Board) | IETF standard (RFC 4287) |
| Content types | Plain text or escaped HTML only | Plain text, HTML, XHTML, XML, Base64 binary |
| Namespace support | Limited | Full XML namespace support |
| Internationalization | Feed-level only via <language> | Per-element via xml:lang |
| Required ID | No (guid is optional) | Yes (<id> is required) |
| Date format | RFC 822 (e.g., Tue, 04 Mar 2026 10:00:00 GMT) | RFC 3339/ISO 8601 (e.g., 2026-03-04T10:00:00Z) |
| Autodiscovery | Informal convention | Standardized <link rel="self"> |
| Extensibility | Via namespaces (informal) | Built-in extensibility model |
| Podcast support | Dominant format (iTunes namespace) | Rarely used for podcasts |
<?xml version="1.0" encoding="UTF-8"?>
<feed xmlns="http://www.w3.org/2005/Atom">
<title>Example Blog</title>
<link href="https://example.com/" />
<link href="https://example.com/feed.atom" rel="self" />
<id>urn:uuid:60a76c80-d399-11d9-b93C-0003939e0af6</id>
<updated>2026-03-04T10:00:00Z</updated>
<author>
<name>John Doe</name>
</author>
<entry>
<title>First Post</title>
<link href="https://example.com/first-post" />
<id>urn:uuid:1225c695-cfb8-4ebb-aaaa-80da344efa6a</id>
<updated>2026-03-04T10:00:00Z</updated>
<summary>This is the summary of the first post.</summary>
<content type="html">
<p>Full HTML content of the post goes here.</p>
</content>
</entry>
</feed>When to use which: Use RSS 2.0 if you're creating a podcast feed or need broad compatibility with existing feed readers. Use Atom 1.0 if you need precise content typing, robust internationalization, or are building a new syndication system from scratch.
JSON Feed is a modern alternative to RSS and Atom, released in 2017. It uses JSON instead of XML, making it easier for many developers to work with:
{
"version": "https://jsonfeed.org/version/1.1",
"title": "Example Blog",
"home_page_url": "https://example.com/",
"feed_url": "https://example.com/feed.json",
"items": [
{
"id": "1",
"title": "First Post",
"url": "https://example.com/first-post",
"content_html": "<p>Full content here.</p>",
"date_published": "2026-03-04T10:00:00Z"
}
]
}JSON Feed supports pagination (allowing access to older entries), attachments (for podcasts), and authors. It is supported by popular readers including Feedly, NewsBlur, NetNewsWire, and Reeder.
To help browsers and feed readers automatically find your RSS feed, add a <link> element to your HTML <head>:
<link rel="alternate" type="application/rss+xml"
title="My Site RSS Feed"
href="https://example.com/feed.xml" />For Atom feeds, use type="application/atom+xml". For JSON feeds, use type="application/feed+json".
Serve your feeds with the correct Content-Type header:
| Format | MIME Type |
|---|---|
| RSS 2.0 | application/rss+xml |
| RSS 1.0 | application/rdf+xml |
| Atom | application/atom+xml |
| JSON Feed | application/feed+json |
<guid> for each item — this prevents duplicate entries in feed readers when you update titles or URLs<description> when possible, not just teasers — readers prefer full content feedsTue, 04 Mar 2026 10:00:00 GMT<atom:link rel="self"> pointing to the feed's own URL for proper autodiscoveryRSS feed readers (also called aggregators) are applications that subscribe to feeds and present updates in a unified interface. Here are the most popular options:
Because RSS feeds are XML documents processed by client applications, they can be vectors for security attacks if not handled carefully:
XXE is the most significant security risk with RSS feeds. A malicious feed could include external entity declarations that, when processed by a vulnerable XML parser, can:
Mitigation: Always disable external entity processing and DTD loading in your XML parser. In most languages, this is a configuration option:
# Python (defusedxml)
import defusedxml.ElementTree as ET
tree = ET.parse('feed.xml')
// JavaScript (avoid xml2js defaults)
// Use a parser with external entities disabled
// PHP
libxml_disable_entity_loader(true);RSS feeds may contain HTML in <description> fields. If a reader renders this HTML without sanitization, an attacker could inject malicious JavaScript.
Mitigation: Always sanitize HTML content from feeds before rendering. Strip <script> tags, event handlers, and other dangerous elements.
If your application dynamically generates RSS feeds from user input (e.g., comments or forum posts), ensure the input is properly escaped to prevent XML injection attacks.