Feeds

Feeds are structured data streams that deliver regularly updated content from a producer to subscribers. They enable syndication and automated aggregation, allowing users to follow many sources in a single place. In web contexts, the most common feed formats are RSS, Atom, and JSON Feed, though the general concept also applies to other data streams such as financial price feeds or sports scores. A feed typically includes metadata about the feed itself (title, description, link, last updated) and a sequence of entries or items, each with a title, link, summary or content, publish date, and a unique identifier.

How feeds work: Content creators publish a feed at a URL. Readers subscribe using a feed reader or aggregator, which retrieves the feed at intervals or subscribes via a push mechanism such as WebSub. Readers present new items to users, often with options to summarize, filter, or organize content. Feeds can be public or restricted; podcasts commonly use enclosures within a feed to deliver media files.

Formats and standards: RSS and Atom are the most widely used XML formats, while JSON Feed offers a modern JSON alternative. Feeds may support features such as pagination, enclosures, or content negotiation. Security considerations include the possibility of tampering and caching; using HTTPS and verifying sources help mitigate risks.

History and usage: Feeds originated in the late 1990s as a means for blogs and news sites to distribute content efficiently. They remain common for content distribution, news aggregation, and podcast delivery, and are also used in enterprise environments for automated data delivery.