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Evaluating Third-Party Ad Tags for Speed

Written by Roy
Sep 26, 2020 • 4 min read
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AdGlare is one of the fastest ad servers in the market. If you're running third-party tags, you may not have that performance boost you were looking for. As a publisher, slow ad tags will likely result in a Google SERP penalty and motivates people to use an ad blocker.

AdGlare has several ways to evaluate the performance of third-party ad tags:

  • Quality Score
  • Loading Speed
  • Quality Assurance Scanner

Quality Score to the rescue

The quality score gives you an idea of how fast the ad tag loads. To calculate the quality score, copy/paste the third-party ad tag in the creative box. Then click somewhere outside the box and it will be calculated within seconds. We're evaluating the following:

  • SSL-Compliancy
  • Load size (in KB)
  • Number of HTTP requests
  • JavaScript Errors
  • If it drops 3P cookies

The score goes from 1 to 100 and is calculated based on industry averages and IAB's LEAN guidelines for lightweight ads. Aim for a score > 80.

This is something you want to avoid:

As a publisher, you can consider refusing third-party tags that don't comply with your standards. There's a good reason for that: heavy tags slow down your web page, destroy the user experience and provoke a Google SERP penalty.

A (really) bad example

In the tag above, Sizmek loads a staggering 3.4 MB of data using 29 HTTP requests for just one ad. That's simply jaw-dropping! No wonder people are using ad blockers. Moreover, the ad has 4 JavaScript errors and drops 3P cookies. This is a perfect candidate for further investigation.

Loading Speed

Whereas the quality score is determined by AdGlare's servers with gigabit connections, users generally have slower internet speeds. We therefore measure how fast the ad is loaded from real-world user data. The averages are visualized by bars. Aim for green bars, which means that the ad loads in less than a second.

Here's an example of slow loading ads:

Quality Assurance Scanner

Investigate third-party ad tags further with AdGlare's Quality Assurance Scanner. A tool favorite by our biggest publishers! It's available in the Enterprise edition and works as simple as copy/pasting the tag in the scanner. We'll report back on potential issues like:

  • GDPR/CCPA cookie dropping
  • Usage of old synchronous tags
  • If the tag is blocked by ad blockers
  • Audio playing without user interaction
  • CPU/Memory consumption

It will also report all JavaScript errors and warnings the tag produces, as well as all HTTP network requests it makes. Here's an example:


It's important to evaluate third-party ad tags for speed and performance. Not doing so may have a severe impact on your page's loading speed, the user experience and you'll risk a Google SERP penalty due to slow loading pages.

AdGlare has the tools and features to scan third party tags to evaluate their performance. Use them before they go live! sentiment_satisfied_alt

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