GTmetrix Performance Blog

News, updates and guides on GTmetrix and general web performance

Updates to CDN Detection, Dashboard and More

This article may contain outdated material

Some of the features outlined in this article are still available. However, the content pertains to the legacy version of GTmetrix.

We’ve made a few updates to our CDN detection, Dashboard behaviour, API usage notifications, and History graphs.

Here’s a breakdown of the latest updates to GTmetrix:


CDN Detection

We’ve improved YSlow’s CDN detection to also check hostnames that are CNAMEs to CDN hosts. CDNs like Akamai use these CNAME aliases to allow their users to have a customized hostname for their CDN delivered resources. These implementations often don’t add HTTP headers however, and YSlow can’t easily detect that these resources are hosted on a CDN.

We also added new CDNs to our list for auto-detection:

  • StackPath
  • Microsoft Ajax CDN
  • Fastly
  • Cloudinary
  • Services that use Akamai’s CDN

Learn more about why CDNs are important.

Dashboard Behaviour

GTmetrix will now remember your Dashboard state when going Back and Forward in your browser. This affects your selected Filter options and paging for the latest reports list.

GTmetrix will remember your Filter Options if you’ve navigated away then back.


This new behaviour will also remember your paging position if you navigate away from the Dashboard.

Paging position is also remembered.

API Usage Notification

For our API users, we will now notify you via e-mail when you reach 10% of your remaining API credits AND when you run out of credits.

You can update your GTmetrix PRO account and add more credits immediately with a Custom plan.

History Graphs

Some of our users have History Graphs that take a long time to load due to numerous reports generated hourly over the years.

Instead of showing a blank space, we added a loading gif to indicate that your History Graph is loading.

History Graphs now show a loading gif before displaying graphs.


Let us know if you run across any bugs or issues and feel free to tell us your thoughts on Twitter (@gtmetrix) or contact us.

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