pubDate

pubDate is an element used in RSS 2.0 to indicate the publication date and time of an individual item in a feed. It provides a standardized timestamp that feed readers can use to sort items, display recency, and determine whether content is new since the last fetch. The value is a string formatted according to RFC 822 (with RFC 1123 variants), typically including a day of the week, numeric day, month, year, time, and a GMT/UTC timezone. Example: 'Sat, 07 Sep 2002 00:00:01 GMT'. The time zone is usually GMT, and different feeds may present minor variations as long as they remain RFC 822 compliant. PubDate is optional in RSS 2.0; if omitted, readers may fall back to other metadata or simply rely on the feed's sequence.

In practice, pubDate enables clients to present chronological lists and to implement caching and delta fetch strategies. It is distinct from the channel-level lastBuildDate, which indicates when the channel itself last changed. In Atom feeds, the corresponding concept is published, which uses an ISO 8601 timestamp; pubDate-specific parsing is not required for Atom feeds but many parsers support both formats for compatibility.