A web feed is a document (often XML-based) which contains content items, often summaries of stories or weblog posts with web links to longer versions. Weblogs and news websites are common sources for web feeds, but feeds are also used to deliver structured information ranging from weather data to "top ten" lists of hit tunes. While RSS feed is by far the most common term, the generic "web feed" terminology is sometimes used by writers hoping to make the concept clear to novice users, and by advocates of other feed formats.

More often, feeds are subscribed to directly by users with aggregators or feed readers, which combine the contents of multiple web feeds for display on a single screen or series of screens. Depending on the aggregator, subscription is done by manually entering the URL of a feed, by clicking a feed: link in a web browser or by various other methods.

Web feeds are most commonly found in various RSS formats or the standardised Atom format.