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This is the archived version of the Zoompf blog. Since our acquisition by Rigor, all our new research and posts on web performance are being published on The Rigor Blog

It’s Never Been Easier to Analyze Third Party Content with Zoompf

 Mark Isham on November 30, 2015. Category: announcements, Product Release

CC0 Public Domain

Today I’m happy to announce the release of some great new features to help you analyze (or ignore) the performance impact of the Third Party Content on your website using Zoompf Web Performance Optimizer.

Third Party Content is any content linked from your webpage over which you do not have direct control. For example, an advertising beacon or externally hosted JavaScript library. First Party Content, on the other hand, refers to content you either host yourself or have the ability to update and change. JavaScript hosted on your servers, images on a separate image server, etc. In general, you can optimize your First Party content but not your Third Party (other than choosing who you wish to partner with).

The new features are designed to help you more easily classify which of your content is First vs. Third party so you can focus your performance improvement efforts on that content over which you have direct control.

Classifying First and Third Party Domains

To begin, let’s dive straight into an example. Go ahead and select New Test from the top level nav, and then Create New Test. Enter your site URL and you’ll immediately see a new expanding section similar to this:


This is a new real-time URL tester that not only tests the validity of the URL you provide, but also sniffs out the domains of all linked resources off the base HTML page. Pick the domains you know are yours (First Party Content) and leave out those that are known Third Party. This will seed the new performance test with the list of domains it should treat as First Party.

Go ahead and click Start Test and wait for the snapshot to complete. When done, if a large percentage of Third Party Content was identified (say you missed a domain in your initial selection), you’ll see a warning like this:


This warning typically only displays if you didn’t select a large First Party Domain in your initial selection above. It could also occur, though, if a large percentage of Third Party Content is loaded by JavaScript execution or linked from secondary resources like your CSS files.

If the warning is in error, just dismiss it and you’ll never see it again for that Performance Test. If it’s accurate, though, then follow the link to update your First Party Whitelist and you’ll see a view similar to this:


This is a list of all Third Party domains detected during the performance snapshot. To see more detail, just click any of the host name links and you’ll see all the linked content, filtered by domain, for that snapshot. For example:


The domain filter option is new, and an extension of the rich content filtering introduced last month.

Hit the Clear button to reset and filter on different domains, file types, or specific file names.


Once you’ve confirmed which domains were erroneously tagged as Third Party, return to the Third Party Hosts view (click the Third Party tab, Hosts sub-tab), select the First Party hosts and then click the Set as First Party toolbar button.


This action will reclassify all linked resources for the selected hosts as first party content, recalculating all totals and rollups to reflect this change. In addition, your selections will be applied to all future performance snapshots as well, so you’ll only have to do this once.

Hit Yes, and the page will refresh with the new totals reflecting your changes.


Notice how the Third Party percentage dropped from 90% to 26%, while the rollup amounts on all the other tabs increased. Click into any tab to see the updated results from your selection.

Now you may have noticed the original warning message above mentioned that this action can be undone later. To (re)classify content as Third Party, simply visit the Hosts sub-tab of the Content tab, and check off those domains that should be Third Party using a similar process to above. This will update the snapshot once again, and also (re)apply to future tests.

blog_time8 In addition, if you visit a specific detail page for an analyzed item, you’ll see options to set as First Party or Third Party at the top of the specific detail page, for example. blog_time11

This makes it easy to correct results as you are digging down into specific details.

Whitelisting and Blacklisting

Okay, we’re almost done here, but there’s one last important topic to cover. You may have noticed earlier I mentioned all changes reflect the current and all future snapshots. This is important to recognize as it means you should only rarely have to administrate your Third Party content list. Once you establish your baseline settings, they’ll just auto-apply for each new test and snapshot.

If you wish to fine tune these settings, you can manage these on a new tab under Settings called Third Party Content.


This page manages your First Party Whitelist (domains to always classify as First Party) as well as Third Party Blacklist (domains to always classify as Third Party). These settings are automatically updated whenever you apply changes using the process in the previous section, but if you wish to fine tune your results further you can do so directly on this page.

For example, in the above screenshot you may have noticed there were a number of subdomains of wp.com listed. To simplify this configuration, as well as automatically handle any new subdomains, you could just replace all those entries with a single entry for wp.com like this:


You can also supply regular expressions in these selections if you want to get even fancier, but i’ll leave that as an exercise for the reader.

In Closing

Managing your Third Party/First Party whitelist is an important step in effectively managing the noise level of your performance test results. With some simple care and feeding, the quality of your results will improve greatly. We hope you find these tools helpful, and as always, we’re very open to suggestions for further improvements.

If you’re not currently using Zoompf Web Performance Optimizer, Contact Us to start your trial today!


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