Tracking Pixel vs Postback URL: Which is Better for Conversion Attribution

Tracking Pixel vs Postback URL

Whoever works with performance advertising knows that conversion attribution and optimization are crucial for success. There are no workarounds here.

This is why at Voluum, we take tracking really seriously. After all, it is the essence of our product! Voluum supports two main methods for tracking conversions – Tracking Pixel and S2S Postback URL.

These methods cover all cases. For some affiliate networks, a third method is available: API integration. But the most popular ones are pixels and postbacks.

Understanding the differences between these two options will help you choose the most suitable method for your needs. 

But firstly, let’s ask and answer: why would you even want to track conversions?

Conversion attribution

Conversion tracking is essential for conversion attribution. This allows you to connect a specific visit (and with it, a concrete ad variation, lander and offer) with a resulting conversion.

Knowing this allows you to learn what works, adjust your message, campaign funnel and advertising strategy towards a more cost-effective approach.

Conversion attribution is the cornerstone of an efficient marketing strategy. Without it, the only thing you are left with is watching your numbers shift without the knowledge of why something is working or not. 

To make conversion attribution possible, Voluum assigns unique IDs to each click on the ad, and then store is to connect different touchpoints of a campaign funnel. These click IDs are then passed to an affiliate network and returned upon conversion. Voluum then matches the click ID that came with a conversion with the one behind an original click to attribute this conversion to a correct event.

The results are clear and consistent reports that allow you to take a deep dive and discover, what is going on with your campaigns.

Now, let’s find out together what kind of conversion tracking system is better to use for conversion attribution – pixel or postback tracking, so in other words… Let’s discover who is going to win this clash of giants!

clash of penguins

Conversion Tracking Pixel

Tracking Pixel, also known as browser-based or cookie-based, is a tracking method that allows users to track webpage visits, ad impressions, conversions, and other types of online activities.

A tracking pixel is an HTML piece of code that can be placed on a landing page or offer page to track the visitors’ actions.

In order to use tracking pixel for tracking conversions of your offers, you need to place the tracking pixel on a confirmation or a thank-you page.

When a user visits the confirmation page your tracker – e.g. Voluum – will be able to register a conversion for that specific ad and campaign specifically thanks to the tracking pixel code.

How? We are able to place and later read the cookie with a unique click ID value that identifies a user along the campaign funnel. This cookie is being placed in the user’s browser when the ad is displayed.

As you can see, tracking your offers with a tracking pixel is very straightforward and does not require a complex technical savvy. It’s simply placing a piece of code on the page right after a conversion happens. And the job is done.


  • A conversion tracking pixel is your ultimate solution when you don’t have many technical resources and you own the “thank you page” (meaning that you don’t buy media on behalf of any 3rd party);
  • It is simple and quick to implement, effortless to use, so you don’t need to be a tech expert – you can start tracking right away;
  • It is a matter of just copying the pixel from Voluum and pasting it into the code of the final thank you page that a user sees after the conversion has happened. Simple as that.


  • Occasionally, pixels might not fire. Why? One of the reasons could be that the user cleared their cache between clicking on a link on a landing page and the actual conversion. In that case, a conversion simply won’t be tracked.
  • Apple implemented Intelligent Tracking Protection 2.0 on Safari which prevents websites from being able to track users’ browsing habits without their permission. Right now, a website can request tracking privileges, but the user has to specifically opt-in. Even if the user agrees for tracking in Safari, unless they interact with that particular website over the period of 30 days all data and cookies will be permanently deleted. All in all, pixel tracking can get pretty difficult on Safari.
  • Additionally, Google announced that their web browser, Chrome, will stop supporting 3rd party cookies from 2022. This will also cause problems for pixel tracking.

Postback Tracking

Postback URL Tracking is also known as server-side or Server-to-Server (S2S) tracking. If you choose this method, a click ID value is generated and sent to your affiliate network via HTTP request.

Later, when a conversion happens, the affiliate network passes this value right back to Voluum. Once this action is completed, you see a conversion in your reports. Having received the value of click ID, Voluum is then able to recognize the exact visit and attribute the conversion to the right campaign.

Simple, right?


  • Using S2S postback URLs is more secure and reliable method to count conversions, thus it is highly recommended to use it whenever you can. Voluum creates unique S2S postback URLs for each account and supports only secure HTTPS format. 
  • S2S postback URLs ensure accurate tracking and stats gathering. This type of tracking happens does not depend on cookies, so it works even if a visitor has cookies blocked on their web browser. For this reason, it is considered one of the most trusted tracking methods.


  • Postback tracking has to be supported by your affiliate network.
  • With other trackers, you would also have to set up appropriate parameters and tracking tokens to accurately pass information. Luckily Voluum has templates for all major affiliate networks that contain all parameters and tokens already set up an a psotback URL ready to submit to your affiliate network. You can earn more about postback URL tracking from our knowledge base.

Hey, what about the API method mentioned before?

That’s right, there is a third method of tracking conversions and it is based on the ad tracker’s API integration with an affiliate network. 

This turns our competition into a three-way duel.

A truel.

This is the most reliable method of conversion tracking, as it happens at the back-end of both platforms. No messy tokens and parameters. When a conversion happens, the affiliate network’s infrastructure pings an ad tracker with all necessary information.

However, as this solution requires a lot of development work on both sides, it is not very prevalent in the affiliate marketing landscape.


  • The most reliable method of passing conversion, fool-proof and secure. Doesn’t need cookies to work.
  • It is a “set-and-forget” solution. Once you perform integration, you don’t have to set anything up, conversions will be passed on along with additional information, such as payout.


  • It is rarely used, as it requires a lot of effort to be implemented.

You will be glad to hear that Voluum uses the API integration for conversion tracking with Clickbank. Read the document that describes the Clickbank integration if you want to learn more.

Clash Of Giants – Who Is The Winner?

By now you should have a fairly good understanding of what the two main tracking methods are and how they work. 

Now it’s time to choose the best method for your own business needs. As I said at the very beginning, tracking is fundamental if you want to become successful in affiliate marketing, so make sure you do it right.

If you ask us, we always recommend using the S2S postback URL option for conversion attribution as opposed to the tracking pixel as we find it far more accurate and secure. But, of course, we encourage to choose for yourself. The important thing is:

With Voluum you can track your conversions as you like 😉

Key Takeaways

  • Tracking is fundamental to being successful in the performance advertising industry;
  • Choose the tracking method that will suit your business needs best;
  • Pixel tracking is quick to implement;
  • S2S postback URL tracking is the most secure and reliable method for accurate tracking and stats gathering;
  • Postback tracking is done in a server-to-server manner and setup requires a tech-savvy approach.
  1. Hello,
    I see no clear winner here. Seems both are used for different purposes as you have described in your article.

    Conversion Pixels are used when you are promoting your own offer on your website, while S2S Postbacks are used in the case of third party offers or offers from affilaite networks.

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