Hosted service

Using this hosted service is free for use, but you will need to get access before it's live to use on your web site.

It's recommended that you host your own version of the client script, which you can download here.

Then initialise the script on your site by adding the following script tag to your site:

<script async defer src="location_to_your/redirect.js"></script>

Once initialised, the redirect.js script will progressively enhance any outbound links on your site and route them through this service to check for link rot.

Why self host the client script?

A few reasons:

You have control over scripts running on your pages
If this domain somehow hangs, your site won't be affected
You can modify the script to suit your needs

What if unrot∙link goes down?

The client script includes an initial, very lightweight, ping to this service. Only when that has replied, does the client script progressively enhance your site.

How the client script works

When the redirect.js script is first loaded, it will send a one off ping to this service to check that it's still available. If it is, it will then start to progressively enhance any outbound links on your site.

This is done using a single event handler (using event delegation). Only external links will be enhanced, and only links that are not already pointing to the web.archive.org domain.

In addition, if your web site uses the h-entry microformat2 (sites like wordpress ), the script will also check for the dt-published property and use that timestamp when finding a web.archive copy of the given URL.

If your site doesn't use the dt-published property, then the archive copy will be the latest available copy that returned a 200 status code.

Note that you can modify the redirect.js file to discover the timestamp in other ways, or to use a different timestamp altogether. The format is described in the self hosted API.

Example using h-entry to show the site at time of publish

A fictional h-entry post that was published in 2014 and includes a link to the "oOOoh" web site.

<span class="h-entry">
  <a href="http://oo00.eu">oo00.eu</a> in
  <time class="dt-published" datetime="2014-03-01">March 2014</time>
</span>

oo00.eu in March 2014