Zoompf's Web Performance Blog

Note: Archived Content

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

Compare Historical Performance, Test Your Competition…and Drugs!

 Mark Isham on June 30, 2015. Category: announcements

So far the response to our new beta version of Web Performance Optimizer has been fantastic! Beyond a completely overhauled user interface, we’ve also exposed a mountain of new data to aid you in your performance testing efforts: third party content rollups, new mobile testing options (iPhone 5&6, Samsung Galaxy, iPad, portrait vs landscape,…), full site content breakdowns, waterfall charts and much more!

At Zoompf we’re not ones to sit still, though. Today I’m pleased to announce another major new feature to our WPO Beta: Performance Comparisons! 

Compare Historical Snapshots

We realize performance testing is an iterative process. To help, we’ve added a new feature that allows you to compare any 2 performance snapshots, allowing you to quickly spot what changed, and how that change impacts your site speed.

Let’s dive right into an example, I hope this won’t give you a headache…


(Click here for an interactive demo)

This new comparison view follows a similar format to the snapshot view, but highlights specifically what changed from one snapshot to the next. So in the above example, you can see that over the course of 5 days, the Zoompf Score dropped 7 points and there was 1 fewer defect found, but the total content size increased by 155 kb. You can also see an uptick in uncached content, which may be worth digging into.

You also get a nice scorecard summarizing all the changes:


Click into any tab to see a side by side comparison of the changes…


And a table summarizing exactly what changed…


Click any specific item to jump straight into the snapshot details to see the full extent of what changed and how you can fix the problem!

To access: you can compare snapshots in 2 ways. First, just click the “View Changes” button on the overview tab of any snapshot page (assuming it’s the second or later snapshot you’ve run for that test).


Or you can use the “Compare” button in the snapshot history page for any performance test.


A/B Testing and Testing Your Competitors

When you compare performance snapshots, you are comparing 2 “points in time” instances of the same performance test. In other words, the same start URL, the same device type, the same scan configuration, but a different time. Apples to Apples. This can be quite useful in finding performance regressions that slip in with new features.

In other cases, though, it can be useful to compare 2 different performance tests altogether. You may wish to do this for A/B testing (does page “A” score better than page “B”?), to compare different device types (Desktop vs. Mobile) or even see how you stack up against your competition. Apples to Oranges.

Our new performance comparison feature allows just that.

From the top level nav, select “View Results” and check off any 2 tests you want to compare, then click the Compare button to launch the comparison. You’ll then see something like this:


(Click here for an interactive demo)

Unlike the snapshot comparison, we are not necessarily focused on changes over time, but rather the current state of affairs. How does site A stack up against B? This view will show you a side by side comparison of all the metrics we track in our tests: performance defects, total content size, unoptimized content, third party content, and more.

For each metric you can dig into the details to see side by side charts like this:


And tables showing side by side comparisons of all the details.


And there’s even a “report card” view where you can get a high level overview of who is “winning” the performance optimization race:


Lots of goodies here…my headache is going away already!

And More To Come…

We’re very excited to release this major new feature for the beta and have a lot more planned still. These features are all a direct result of your great feedback, so please keep the requests coming! (You can contact us here).

If you’re not already a Zoompf Web Performance Optimizer user, contact us to learn more and see a demo. I think you’ll be amazed the level of detail our reports provide, there’s nothing else like it. You can also learn more on our product features page.

Not ready for a demo yet? Test your site performance with our free performance report. Still not convinced? Try our daily performance alerts to get notified when your site slows down…also free!


Have some thoughts, a comment, or some feedback? Talk to us on Twitter @zoompf or use our contact us form.