Media Types

Link Relations


Ongoing notes on designing, documenting, and registering link relations.

  1. General Notes
  2. Registries
  3. List of Link Relation Types


General Notes

Random notes and comments kep[ here until further categorization and editing.



Some historical documents on Links and Link Relations:



There are multiple sources that act as "registries" for link relation values.

The process of registering new link relation values at each of these locations is different. It is also a bit unclear why a link-rel-value author would select one registry over another or whether the author should engage each registry when attempting to standardize a link-rel-value.

Below are my notes on the process.


IANA Link Relations

RFC5988 (Web Linking) establishes the Link Relations Registry:

"This specification establishes the Link Relation Type registry, and updates Atom [RFC4287] to refer to it in place of the ''Registry of Link Relations''."


Below are some valuable resources when working w/ the IANA Link Relation Registry to register your link relation values:


The process in this section is bogus. I am currently working through an Internet Draft process w/ IETF to create an informational RFC for two selected link relations. You can follow that progress here. Once the process if completed, I will transfer my notes to this section of the site (MCA).

The process for registering a link-rel-value (referred to as a link relation type in RFC5988) with the IANA Link Relations is outlined below.

Join the Link Relations mailing list
Before attempting to register your link relation type, join the mailing list and 'hang out' for a while to get a feel for how things work. This is a relatively quiet list, so it might help to introduce yourself in order to get things 'going.'
Publish your Link Relation Type
Be sure to publish a clear description/definition of your link relation type at a "permanent, readily available, and public" URI. This URI will be used when applying for registration.
Obtain an account at the ParamsR.Us tracking site
An easy way to apply for a registration is through the ParamsR.Us tracking site. All you need to do is obtain a login account to get started.
Submit your registration
The tracker allows you to submit your registration, but it does not walk you through supplying each field. Instead you enter the Link Relation Type (called a 'Registry Key' at the tracker site) and a block of text that represents the complete registration template. Section 6.2.1 of the Web Linking RFC5988 has a sample template you can use.
Monitor the mailing list for feedback
After posting your completed template, monitor the mailing list and the tracking site for progress. You should recieve feedback in 14 days or less.

My Experience (2011-08-05)

In the summer of 2011, I set out to register two link relation types with the IANA to learn the details of registration at the IANA. Below is my experience.

  1. Selected two link-rel-types from my Collection+JSON media type.
  2. I was already a member of the mailing list.
  3. I completed registration templates for each of the two link relation types and posted these templates.
  4. I logged into the ParamsR.Us site and created twoentries using the templates I previously created.
  5. I posted a note to the mailing list annoucing the two new entries and inviting comment/feedback.
  6. (more to come...)


Microformats Existing Rel Values

The W3C document on HTML5 mentions the Microformats site as the place to register link-rel values:

"Extensions to the predefined set of link types may be registered in the Microformats wiki existing-rel-values page."


Below are some valuable resources when working w/ the Microformats group to register your link relation values:

  • The Microformats Wiki contains the most recent definitions and also ongoing work to define new microformats.
  • The existing rel values page contains all the rel-values currently tracked by Some of the lists here show real-values that are "non-HTML", "obsolete", or in various forms of "in-progress."
  • Discuss Microformats points to email lists, IRC channel, and blogs where Microformats are covered.

Registration Process

The process for registering a link-rel-value with the Microformats Existing Rel Values is outlined below.

All edits to the Microformats wiki are automatically announced to the IRC channel (#microformats on freenode) by a 'bot.' It's a good idea to join that channel (on freenode) and monitor any feedback that appears there.
Obtain an account at the Microformats Wiki site
Login/Create Account. I recall this to be a very simple process (no screening, IIRC)
Review the page that holds link rel values and determine which section you plan to edit to add your link-rel-values
Make sure you understand the layout of the Microformats Existing Rel Values page. While most all sections are editable, only a few of them are meant to be actively edited.
Edit the page to add your link-rel-values.
Once you find the section that applies to you (POSH usage, non HTML rel values, brainstorming, etc.), edit that section. Be sure to add a helpful comment, too.
Monitor the page for discussion and feedback.
You can "watch" the existing-rel-values page so that you get any feedback relating to your edits.

My experience (2011-07-22)

In the summer of 2011, I set out to add some new rel values to the Microformats wiki to learn the details of contributing link-rel-values. Below is my experience.

  1. Selected link-rel-values from my Maze+XML media type.
  2. Joined the IRC channel to monitor activity there.
  3. Modified the non HTML rel values list to include several new values (collection, east, exit, maze, north, south, west). I also added a helpful comment to the edit.
  4. I posted a note in the IRC channel to let others know who I was and to feel free to provide feedback
  5. Within minutes Tantek Çelik (founder of the site) posted feedback on the IRC channel. He acknowledged that some entries were "interesting" (north, south, east, west); one was not defined properly (he suggested updating the collection description to better express a "relation" between the context resource and the target resource- which I did); and he rated one value (maze) an "abuse of rel" and asked me to remove it from the list (which I did).
  6. It's been about a week now, and no other feedback has been provided. I suspect the "process" is complete for now.


Dublin Core metadata

The process for registering a link-rel-value with the Dublin Core metadata is not at all clear to me at this time. If anyone has details, pointers to documentation, etc. please feel free to send me an email: mca -AT- mamund -DOT- com.