This Pace specifies an "in-reply-to" relation for referring to the atom:entry "this" entry responds to (the "parent entry").



Revised: 19-Jul-2004 by KenMacLeod


Many entries are related to other entries as replies. Examples:

Many people who maintain "recent comment" feeds currently put a link to the parent post within their content element (rendered as part of the HTML content), but it would be more useful to make this relationship explicit in a separate element.

The proposed relation would provide a way for feed publishers to establish that an entry replies to another entry, by linking to its parent entry. It would be up to each client to decide whether to render this relationship, and if so, each client can decide on an appropriate UI.

See MessageThreading for references on message threading.

See for an example thread and comparison with "entry feeds" and wfw:commentRss.

See [WWW]atom-syntax thread for the discussion that prompted clarifying the relation name from "parent" to "in-reply-to". Subsequent discussion also strongly objected to implicit support of "distributed" replies, so this proposal constrains the defined behavior to only single feeds where all entries are present.

Example sites


Add the following to section to the protocol draft -00 section, 3.4.1 rel:

[[ note: link construct markup and location of normative specification (protocol or format) are currently under discussion. This proposal is written in the style of the -00 drafts.]]

[[ note to editor: the definition of this is adapted from RFC [RFC]2882, sec 3.6.4]]



  <title>First post!</title>
  <link rel="alternate" type="text/html" href=""/>

  <title>First comment!</title>
  <link rel="alternate" type="text/html" href=""/>
  <link rel="in-reply-to" type="application/atom+xml" href=",2004-01-01:/blog/1"/>


This proposal does not add any requirements for feed publishers. It allows publishers to explicitly state cross-entry relationships, but does not require them to do so. It allows clients to expose relationships between entries in their UI, but does not require them to do so.


See also : [WWW]ThreadsML

[AnneVanKesteren] +1

Changes from [WWW]21-Jun-2004 ([WWW]diff):

I think Atom should use the Dublin Core element <dc:relation>, as its semantics is already defined there. <dc:relation> also has the bonus that it defines other relation issues, like IsBasedOn (supersedes or «re-issuance» of resources) and such.

is a refinement of

which in turn is a refinement of

Thus, atom:in-reply-to is a dc:relation. In the Dublic Core mapping we can indicate that atom:in-reply-to can be interpreted as a dct:references.