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Programmatic: Pixels in Advertising 101

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Programmatic Advertising 101: Pixels

Learn the basics of Programmatic Advertising with Ted Jordan! Today, we explain what a pixel is in advertising with simple words and expertise. Ready to learn?

What are pixels?

Pixels (also called tracking pixels, marketing pixels, advertising pixels or tracking tags) are used to track actions in advertising. They collect information about user behaviour and their interaction with content. Pixels can also track the user location, their screen resolution, their browser or the device they use.

Pixels are pieces of code, usually implemented as 1×1 images or as JavaScript tags on webpages, programmatic ads, emails, etc. Usually, JavaScript tags are able to track and collect more information than image tags.

When a user sees an ad or visits a webpage containing a pixel, the pixel fires: the pixel is activated and sends data to a server. The data is then available to the advertiser or to the website owner.

Timeframe when the pixel fires can be personalised if you want to track retention: a website owner can set a pixel to fire after 7 seconds, for example.

The main difference between a pixel and a cookie is that a pixel can track data between various platforms while a cookie can’t. Cookies are used to store user data and preferences on a device while pixels track user interactions and send these directly to a server.

What’s the difference between a tracking pixel and a beacon?

There is no difference between a tracking pixel and a web beacon. A beacon is just another name for a tracking pixel, like “marketing pixel” or “conversion pixel”.

Types of tracking pixels in advertising

In advertising, pixels are used to track a large range of data such as ad impressions, open rates for emails, reporting accuracy, conversion tracking. The data is analysed and programmatic or digital campaigns are optimised accordingly.

There are 3 main pixel types used in advertising: impression pixels, retargeting pixels and conversion pixels.

Impression pixels

Impression pixels are mainly used to track ad impressions in digital advertising. Advertisers use impression pixels to track the number of times their ads are seen, for analytics purpose and to compare these numbers with the ones given by programmatic platforms, for example.

Depending on platforms, websites, ad placements and formats, impression pixels can fire when an ad is seen in its entirety or only at 20%, 30%, 50% or 75%.

For example, imagine a 300×250 display ad (=75,000 pixels). If the viewability is set at 50%, the impression pixel contained in this ad will only fire if at least 50% of the ad pixels are displayed. Or we can say if 37,500 pixels (50% of 75,000) or more are seen by the user.

Retargeting pixels

Retargeting pixels are used to retarget website visitors who performed a specific action (visited a page, added an item to their basket but did not purchase it, etc.).

For example, a retargeting pixel could be used to track website users who did not buy anything on the website in order to display paid ads to them just after they left the website.

Retargeting pixels track website users to display paid ads to them so they perform a specific action afterwards.

Conversion pixels

Conversion pixels fire when a conversion is made by a user: a sale, sent form, click to a specific page, newsletter registration, etc.

The data registered by the tracking pixel is then analysed to get insights about converters, in order to increase conversion rates and decrease the CPA (Cost Per Action). It’s also important to track converters to exclude them in some digital marketing campaigns. Doing this allows advertisers to save money by not advertising specific offers for first buyers to converters, for example.

Advantages and disadvantages of using pixels in advertising

Using pixels in advertising presents some pros and some cons. While it helps advertisers track specific events, actions or data, users may dislike their use because they like to protect their data and keep it private.


Some of the advantages of using pixels in advertising are:

  • Better understanding of users’ behaviour.
  • Showing custom ads to users based on their hobbies, for example.
  • Reporting accuracy.
  • Identifying bots (so advertisers won’t pay for “fake traffic”).
  • Understanding user patterns while visiting websites.
  • A/B testing.
  • Personalised web experience (based on specific criteria).


Pixels are extremely useful but can cause controversy. Some of the disadvantages of using pixels in advertising are:

  • Users lack of trust regarding the use of their data (data protection).
  • Latency and long loading time of websites if too many pixels are implemented.
  • Website performance affected by piggybacking (several pixels are implemented in a container tag).
  • Spam (spammers integrate pixels in their emails: if a user opens a spam mail, spammers know that the email address is correct and send more spam mails).
  • Regulations and rules about pixels vary by jurisdiction, county or country.

Pixels in advertising

Best practices

When using tracking pixels, follow these best practices:

  • Limit the number of pixels
    Fewer pixels means fast loading time of your website.
  • Test your ads, emails or webpages
    Make sure implemented pixels are firing correctly after implementing them.
  • Be intentional
    Make sure each pixel tracks valuable information (such as conversions) and only use the necessary pixels on each page.
  • Track demographic
    Track demographics to target specific demographics in your paid campaigns.
  • Respect users’ privacy
    Allow users to opt out of being tracked and follow regulations (such as GDPR for European countries).


After implementing a tracking pixel, double-check it works as intended. If it doesn’t, here are some tips about pixel troubleshooting:

  • Find your pixel
    The first step when troubleshooting pixel issues is to find your pixel. Can you find it in your HTML code and is the code correct? Is it placed in your website header section? Is it placed just once?
  • Give it some time
    Some platforms need time to start recording actions: a pixel may be active within seconds or after 24-48h.
  • Use a pixel checker to save time
    If you implemented a pixel from a specific tag manager, such as Facebook, you can use a Chrome extension to easily troubleshoot pixel issues. For example, Meta Pixel Helper.

If you need help with campaigns set up, we recommend that you join our Programmatic Advertising Course to learn how to do it like a pro.

Do you want us to manage your campaigns? Contact us now!