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Automatically adding new pages to watch from existing results

By Stephen, Updated 3 January, 2024

Think of the situation where you are watching your favourite ecommerce website, and you want to start automatically watching any NEW pages for changes.

For example, you might be interested in a list of search results for a product, but then you also want to follow/watch those product pages for changes (maybe price changes, availability etc)

Since version 0.45.11 it is possible to use the built in API to ask to insert a new link into its database, as a plaintext list of links (with a tag/group as an optional argument), we can use the 'notifications' tab to tell to notify itself to add a new link :)


Here's how! In this example we will use CashConverters as our example.



Step 1 - Add the website URL and configure the filters

Using the current URL, copied and paste from your browser, as the URL in changedetection to watch.



Now in this case, the VisualSelector is not quite what we want, because we are only interested in all of the links to the products, additionally we are interested in the "HREF" part of the "A HREF" part of the link so that we can see what the products link is.



Fortunately, they make it super easy for us, the link is clearly marked with the CSS class name  product-item__price 

So then to get a list of URLs for products, we can use xPath to ask it to extract the "href" part for us, and only return that list.

We "simply" use the Filter Rule  //a[@class="product-item__title"]/@href 

Ah but wait! We need to be sure we have the full link, including https:// and the domain name/website URL.

Change to use the Filter Rule  xpath:for-each(//a[@class="product-item__title"]/@href, function($a) { concat("", $a) }) 

( We will make this easier in the future with some plugins that will support easily appending text to each line of results )


Showing how the filter looks for adding the domain to automatically discovered links


Now we check out the Preview or Difference Page output, and we can see a nice list of links

List of links discovered for automatic following


Step 2 - Automatically importing the URLs via the API

The built-in API supports importing a list (plain-text) of URLs with an option organisational tag/group

Using that, we will make "notify" its own API of any changes to that URL list


Make sure your API access is turned on, and you have the key ready (Visit  Settings > API )



We will use that API key in our notification URL, So the URL to notify (to automatically import the list of URLS) would be (careful to include the + at the start, this signifies that it should be a "http header")


or in the case that you're using our beloved subscription service


Use "post://" for non-SSL and "posts://" if your installation lives on a HTTPS protected address.

And set the Notification Body to only "{{current_snapshot}}" then you can press Send test notification, this will send all of those URLs for population in


Showing how to configure the API to automatically add links


Once you click "send test notifcation" with {{current_snapshot}}, you should then see all those links in  your watch list


List of automatically added links from website


By default, it will only add "new" links


Have fun, and experiment! Happy change detecting :)