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webmention)
Webmention is a simple way to notify any URL when you link to it on your site. From the receiver's perspective, it's a way to request notifications when other sites link to it. Webmention is a modern update to Pingback, using only HTTP and x-www-form-urlencoded content rather than XMLRPC requests. Webmention supersedes Pingback.
Overview
A typical Webmention flow is as follows:
- Alice posts some interesting content on her site (which is set up to receive webmentions).
- Bob sees this content and comments about it on his site, linking back to Alice's original post.
- Using Webmention, Bob's publishing software automatically notifies Alice's server that her post has been linked to by the URL of Bob's post.
- Alice's publishing software verifies that Bob's post actually contains a link to her post and then includes this information on her site.
Protocol Summary
If Aaron's blog supports receiving webmentions, and Barnaby's blog supports sending webmentions, then this is how they interact:
- User Aaron posts a blog post on his blog
- User Barnaby writes post on his blog that links to Aaron's post.
- After publishing the post (i.e. it has a URL), Barnaby's server notices this link as part of the publishing process
- Barnaby's server does webmention discovery on Aaron's post to find its webmention endpoint (if not found, process stops)
- Barnaby's server sends a webmention to Aaron's post's webmention endpoint with
-
source set to Barnaby's post's permalink
-
target set to Aaron's post's permalink.
- Aaron's server receives the webmention
- Aaron's server verifies that
target in the webmention is a valid permalink on Aaron's blog (if not, processing stops)
- Aaron's server verifies that the
source (when retrieved, after following redirects) in the webmention contains a hyperlink to the target (if not, processing stops)
Unmentioned but implied (and vaguely mentioned in the pingback spec):
- Aaron's server displays the information about Barnaby's post somewhere on Aaron's post.
- If a
u-url is present at the source, then the receiver could use that to markup the display and default to the source if not found.
See comment: how to accept a comment for more details on accepting comments in general and displaying them.
Implementations
IndieWeb Examples
The following users/sites have implemented sending and or receiving webmentions, in rough chronological order:
Aaron Parecki with p3k
- Aaron Parecki using p3k on aaronparecki.com as of 2013-05-26. Details:
- All posts send webmentions (as of 2013-05-26 first (semi-)automatic webmention sent on 2013-03-31) upon posting (asynchronously with posting UI, no results reported).
- Events, notes (including RSVPs), replies accept webmentions (as of 2013-05-26)
- Discovery with both:
rel="webmention" and rel="http://webmention.org/" links in head, and HTTP Link: rel="http://webmention.org/ header
- Notes (including RSVPs), replies have an input form for pasting in your comment URL to conveniently send a manual webmention (as of 2013-10-12)
Ben Werdmuller with Known
- Ben Werdmuller using Known (idno ) on werd.io as of 2013-05-31. Details:
- All(?) posts send webmentions as of 2013-05-31 and accept as of 2013-06-??
- Discovery with both:
rel="http://webmention.org/" and rel="webmention" links in head, and with HTTP Link: <http://werd.io/webmention/>; rel="webmention"
Barnaby Walters with Taproot
- Barnaby using Taproot on waterpigs.co.uk as of 2013-06-11 (per git). Details:
- All notes and articles accept (as of 2013-06-20) and send webmentions (as of 2013-06-11) upon posting (posting UI returns response content to the browser, then synchronously sends webmentions)
- Incoming webmentions for notes and articles are parsed and stored, displayed for notes (comment updating as of 2013-06-23) but not yet articles
- Discovery only with HTTP
Link: <http://waterpigs.co.uk/mentions/webmention/>; rel="http://webmention.org/"
Jeremy Keith with adactio.com
- Jeremy Keith on adactio.com as of 2013-09-15. Details:
- All blog posts accept webmentions
- Discovery only with:
rel="webmention" link in head
- Blog posts have an input form for pasting in your comment URL to conveniently send a manual webmention
Barry Frost with barryfrost.com
- Barry Frost on barryfrost.com as of 2013-09-15[1][2]. Details:
- All(?) posts send and accept webmentions
- Discovery with:
rel="webmention" link in head, and HTTP Link: <http://barryfrost.com/webmention>; rel="webmention" in header
- Posts have a hyperlink in footer "How to comment on this post" to instructions detailing posting an h-entry with h-card and how to send a webmention.
Christian Weiske with stapibas
- Christian Weiske receiving webmentions on cweiske.de as of 2013-10-22. Details:
- All posts accept webmentions using stapibas
- Discovery only with HTTP
Link: <http://cweiske.de/stapibas/xmlrpc.php>; rel="webmention"
- Approach for sending webmentions (with fallback sending of pingbacks)
- https://github.com/pear2/Services_Linkback/blob/master/src/PEAR2/Services/Linkback/Client.php#L236
- check self Atom feed, if there are updates then proceed with discovery/sending for each update, for each link in the update: do a HEAD request first, do discovery for webmention endpoint, if none found, do discovery for pingback endpoint, if none found and the resource is
'application/xhtml+xml' or 'text/html', do a GET request, do discovery for webmention endpoint, if none found, do discovery for pingback endpoint. send webmention if an endpoint was found, otherwise send pingback if an endpoint was found.
Bear with bear.im
- Bear on bear.im as of 2013-12-01.
- All posts accept webmentions and send webmentions for new and updated posts
- Full Discovery for link headers, links in html head and body
- webmention handling done by the Python library ronkyuu
Kartik Prabhu with kartikprabhu.com
- Kartik Prabhu on kartikprabhu.com as of 2013-12-03.
- All articles & notes accept webmentions
- Articles have an input form for sending a manual webmention inspired by adactio.com. The form prompt links to the webmention endpoint.
- Webmentions are saved as responses and appear below the article classified according to response type.
- Webmentions are sent manually for all posts.
Pelle Wessman with webmention.herokuapp.com
Jeena with jeena.net
-
Jeena Paradies using a home grown Rails app on https://jeena.net as of 2013-12-06. Details:
- All homepage, blog posts and notes, photos, comments and events accept webmentions
- Discovery with:
rel="webmention" Link: in HTTP header
- Sends webmentions on create, update and delete, no salmentions yet
- Has a manual form
- Homepage receives webmentions and notifies him per email
Christian Kruse with wwwtech.de
- Christian Kruse using a home grown Phoenix app on https://wwwtech.de as of somewhen in 1998. Details:
- All homepage, blog posts and notes, photos, comments accept webmentions
- Discovery with
rel="webmention" in HTTP header and HTML document
- Sends webmentions on create and update, no salmentions yet
Andy Sylvester with WordPress Webmention plugin
gRegor Morrill with ProcessWire plugin
- gRegor Morrill sending and receiving webmentions on gRegorLove.com as of 2014-02-04.
- Using a custom plugin I developed for ProcessWire; previously a plugin for Nucleus CMS
- All articles can receive webmentions
- Webmention endpoint is broadcast via Link: HTTP header and <link> element
- Incoming webmentions validate the target is a valid URL on gregorlove.com and the post ID in the URL is valid.
- Webmentions are parsed and further validated asynchronously. Replies/mentions are displayed interleaved with "local" blog comments..
- More implementation notes
Glenn Jones with node webmentions module
- Glenn Jones using node.js module github.com/glennjones/webmentions on glennjones.net as of 2014-02-19.. Details:
- All notes accept webmentions
- Discovery only with:
rel="webmention" link in head
- The notes editor has an input for the
in-reply-to URL
- The webmentions module allows pinging of webmention between any sites
- Yet to implement: full authorship parsing, updates, deletes.
David Shanske with WordPress plugin
Ben Roberts with ben.thatmustbe.me
- Ben Roberts sending and receiving webmentions on ben.thatmustbe.me as of 2014-04-24
- Parsing replies, mentions, and likes. Rsvps are handled as just mentions currently.
- Discovery with both:
rel="webmention" and rel="http://webmention.org/" links in head, and HTTP Link: rel="http://webmention.org/ header
- Currently uses vouch and a whitelist while all others are sent to moderation.
- Processing happens asynchronously by cron job.
- Submissions return a link for queue record that returns a status as a
Webmention-Status header as well as a minor note in the body.
- Attempting to keep implementation notes as a modified spec at webmetion0.2-b1
- Sending is done automatically when post is made.
Will Norris with webmention.herokuapp.com
Joel Dueck with thelocalyarn.com
- Joel Dueck receiving webmentions on thelocalyarn.com as of 2014-09-23.
- All posts accept webmentions as well as traditional comments.
- Webmentions (if valid) are logged to a text file and sent to Joel via email. Those that pass moderation are manually added to the target post as a comment (which on this site means it is included in the blog and sent to email and RSS subscribers as well as being appended to the target post).
- Endpoint is a modified version of Jeremy Keith's webmention.php.
- Webmentions sent manully. More to implement. To-do list is long. Site is running Textpattern CMS, so a complete webmentions plugin is both feasible and ideal.
Dan Lyke with www.flutterby.com
- Dan Lyke receiving webmentions on Flutterby.com blog entries as of 2014-10-10.
- Webmention endpoint is broadcast via <link> element and <indie-action> element.
- Currently only displays links on title text back to source URLs
- Johnny Oskarsson receiving webmentions on joskar.se as of 2014-10-23.
- Webmention endpoint is broadcast via Link: HTTP header only.
- Pages marked up with h-entry in-reply-to show up as comments, others won't show up at all. (but they will be logged)
- Webmentions are sent manually for now.
Stuart Langridge with Pelican additions
- Stuart Langridge sending and receiving webmentions on kryogenix.org as of 2014-11-29.
- Write up linking to various bits of code for Pelican, the Python static site generator, at "Enabling Webmentions".
- Webmention endpoint is declared in the HTML with a <link> element, because HTTP headers are a pain in the behind to set up by comparison.
- Uses Pelle Wessman's webmention Heroku endpoint as endpoint, and then some Python to fetch and bake in webmentions on site regeneration, and some JS to pull them in live.
Giovanni Parra with Jekmentions
- Giovanni T. Parra receiving webmentions on fiatjaf.alhur.es as of 2015-02-28.
- Wrote Jekmentions, a small service that works as a webmention endpoint for Jekyll sites hosted on GitHub that sends the webmentions received as files in commits to the GitHub repository.
- Webmentions are sent manually for now. Some are being sent, but only through brid.gy to twitter.
Amy Guy with rhiaro.co.uk
-
Amy Guy sending webmentions automatically for all links on all posts on rhiaro.co.uk as of 2015-05-?.
Sarven Capadisli with csarven.ca
Alex Kearney with IndieAnndroid
Peter Molnar with WordPress
Jason Garber with FrancisCMS
-
Jason Garber using FrancisCMS on sixtwothree.org as of 2016-01-27. Details:
- All posts, links, and photos automatically accept webmentions. Replies, shares, and likes are reverse syndicated via Bridgy.
- Post, link, and photo permalink pages have an input form for pasting in your comment URL to manually send a web mention.
- Discovery with:
Link: <https://sixtwothree.org/webmentions>; rel="webmention" HTTP header and <link rel="webmention" href="https://sixtwothree.org/webmentions"> in the HTML's <head>.
- Webmention source URLs are parsed using the microformats2 Ruby gem.
Libraries
Sending
For webmention endpoint discovery:
Handling
Handling receiving webmentions:
For parsing the mentions, the following may come in handy:
Notifications
The following tools show how a notification could be sent upon receiving a webmention
- PHP to email
- Javascript
- bear is working on this...
- XMPP
- - bear is working on this...
Publishing Software
Some open source publishing software supports webmentions:
- Known personal publishing software sends webmentions and accepts webmention comments (including webmention updates), and likes
- FrancisCMS personal publishing software similarly sends and receives
- WWWTech personal publishing software similarly sends and receives
- phorkie sends and accepts webmentions to notify remote instances about forks
Some additional publishing software, portions of which are open source, supports webmentions:
- p3k sends webmentions for all posts and accepts webmention comments on events, notes, replies, RSVPs
- Taproot
Plugins exist for some open source publishing software:
Services
Some services one can use to receive or send webmentions. Alphabetical.
Bridgy
brid.gy is a service that sends webmentions for comments/replies, likes, and reposts on Facebook, Twitter, Google+, and Instagram posts. It uses original post discovery to find target links for the webmentions. GitHub repo here.
Bridgy Publish also supports webmention as a mechanism to trigger POSSEing to Facebook, Twitter, and Instagram.
checkmention
https://checkmention.appspot.com/ lets you test your webmention implementation on your indieweb site, and whether it robustly detects certain types of XSS attacks. It also allows you to test for authorship spoofing.
jekmentions
jekmentions is a service that works as webmention endpoint and saves the received webmentions in a GitHub repository, so that they can be used and shown in a Jekyll blog.
mention-tech
mention-tech is a service that can receive webmentions on behalf of anyone via both webmention directly, and a web form on its home page.
node-webmention-testpinger
node-webmention-testpinger is a tool to ping your site with a variety of webmentions markup. Contains copies of a couple of real world examples of mentions that it enables you to ping locally to a development copy of your site.
node-webmention-testendpoint
node-webmention-testendpoint is tool to test your webmentions client. Generates a demo-post and a demo-endpoint to test if your client parses the webmention-endpoint correctly and to check if the ping body is transmitted correctly.
stapibas
stapibas is a self-hosted service to send and receive webmentions for websites and blogs.
It can be used to send out webmentions and pingbacks for new posts on static sites.
Telegraph
Telegraph is an open source project and hosted service for sending webmentions and pingbacks. You can use it to send mentions to all links on a page, or send a webmention with specific source and target.
webmention.herokuapp.com
webmention.herokuapp.com is an open-source project and hosted service for receiving webmentions for registered sites and allowing those to be displayed through javascript.
webmention.io
webmention.io is an open-source project and hosted service for receiving webmentions and pingbacks on behalf of your indieweb site.
Tools
Tools you can install to send webmentions
Firefox Addon
Wish List
- A tiny, no-dependencies js file which can fetch indiecomment data from webmention.io and dump it into an element, enabling 2-step indiecomment support:
- Add a <link> to webmention.io
- include this script and add some
<div data-indiecomments data-url="blah"></div> element where you want them to appear
Resources
How to test webmentions
See Implementation Guide.
Implementation Details
See Implementation Details.
FAQ
See Webmention FAQ. Please read this before filing an issue or adding to brainstorming.
Issues
See Webmention Issues.
Brainstorming
See Webmention Brainstorming.
Articles
Blog posts and articles about webmention (newest first)
Extensions
See Also
