RSS identity reference

Feed identity glossary

A compact reference to the terms used across RSS, Atom, JSON Feed, podcast syndication, discovery, and identity systems.

Identity terms

Feed ID

An immutable application or registry identifier for a logical publication, distinct from its current URL.

GUID

The RSS item element used to identify one entry. It may be a permalink or an opaque string.

Atom ID

A required permanent IRI for an Atom feed or entry.

JSON Feed ID

A required string that uniquely and durably identifies a JSON Feed item.

Feed fingerprint

A byte, structural, or semantic signature used to compare feed observations. Different fingerprint types answer different questions.

Discovery terms

Canonical feed URL

The preferred current address for retrieving a feed.

Alias

A historic or alternate URL related to the same logical feed.

Autodiscovery

An HTML link rel="alternate" declaration that points feed-aware software to RSS, Atom, or JSON Feed.

Resolver

A service that accepts a URL or ID and returns the associated feed record plus evidence.

Format terms

RSS 2.0

An XML web syndication format organized around a channel and items.

Atom

An XML syndication format with required feed and entry IDs and typed link relationships.

JSON Feed

A JSON-based feed format with required item IDs and explicit page, feed, and attachment fields.

Namespace

An XML mechanism that allows extensions such as full content, media, Atom links, or podcast metadata without colliding with core element names.

Registry terms

Observation

A time-stamped record of what a system fetched or parsed.

Assertion

A claim made by a publisher, user, or integration.

Inference

A conclusion derived from observations and rules, such as a likely alias relationship.

Tombstone

A retained record explaining that an ID was merged, retired, or replaced rather than silently reused.