What Is a Third Party Ad Server?

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  • Post last modified:January 21, 2021

What is a Third Party Ad Server?

A third party ad server is a technology company with expertise in managing, serving, tracking and reporting of online display ads.

As the name suggests, the owner of this server is a third party who does not have direct access to the websites the ads are served but only provides the creatives. It is, therefore, also known as “Advertiser-side server”

Ads are uploaded into an ad server and an ad tag is generated. Advertisers then use that ad tag to serve ads into websites or mobile applications. And as the campaign runs, the ad server the reports the ad performance.

The platform is used by advertisers to host and deliver ads to websites and mobile apps. Additionally, these servers allow ad optimization and campaign management  while generating detailed reports on the creative being served.

First-Party vs. Third-Party Ad Server

1st party ad servers are used by the publishers. They are, therefore, also known as the “publisher side ad server” or the supply side servers. These are the first links in the entire process of serving the ads. 

In a first party ad serving process, the publisher will be hosting and serving the creatives. This means that the advertisers will send the creatives to the publisher who will  host and serve the ads into the publisher’s website.  

Therefore, first party servers are used for ad tag generation, placement, and inventory management. 

Third party ad servers on the other hand belong to the demand side (advertisers) of the ad serving process. These are used for ad targeting, campaign management, optimization and result analysis. 

Here are some other uses for a third party ad server:

  • Third-party ad servers are often used for A/B and multivariate testing.
  • Ad viewability audit check and tracking, with the rise of the importance of ad transparency.
  • Quality check media buys across DSPs, ad networks and publishers.
  • Tracking the user journey through ad engagements and click throughs.

How do third party ad servers work?

When a user visits a website, the browser sends a request to the server asking for page content. The ad tag placed on the page then sends a request to the publisher’s server. The 1st party server then retrieves the user data and forwards it to the advertiser’s third party ad server. 

The latter then matches the creatives according to the requirements, the targeting options, user profile and sends the right creative back to the publisher’s server. Finally, the ad gets displayed for the user. 

We summarise it into the following steps:

  1. When a user visits a website, the browser sends a request to the server asking for page content.
  2. The publisher’s server returns the HTML and renders the page content.
  3. The publisher’s server receives a request to select an ad slot on the page.
  4. Based on targeting information, the publisher’s server choses a relevant ad campaign. 
  5. The publisher’s server now sends the ad markup (a third party ad tag) to the website.
  6. The ad markup triggers a request to the advertiser’s ad server.
  7. The advertiser’s ad server sends back an ad to the publisher’s website.
  8. The ad is displayed. 

Check out the diagram below to get more clarity on the process:

third party ad servers

In current times, there is a very thin line of difference between the work that both the servers can do. Most of the advanced servers that we have today can do both with the network managers having access to both dashboards simultaneously.

Benefits of third party ad servers

In addition to managing the ad campaigns, there are many advanced features that third party ad servers provide to the advertisers. 

Various versions offer customised and super specific targeting which go beyond the traditional targeting parameters like geo location, device, browser, etc. 

Here are some benefits of a 3rd party ad server for advertisers:

  1. All in one ad serving for cross platform campaigns which helps advertisers to keep control on all steps of the media buying process.
  2. Automatic optimization where analytics like CTR, conversions, etc are self generated which help the advertisers to reapply the campaign to other places later on.
  3. Options for customisable rich media (like video templates) is available to the advertisers for embedding into the existing codes. 
  4. Data collection and analytics offered by third party ad servers is completely transparent which allows you to understand the campaign performance and optimise it for better results. 

This article is a part of our comprehensive guide on “What Is An Ad Server And Why You Should Use It?


A third party ad server gives you better control and transparency. Request a demo with MobileAds now!



Alvin is the Founder and CEO of MobileAds.com. He is a go-getter, and adventurous guy who believes in working smart to gain success in his business ventures and in life. He also founded RichMediaAds.com and MobileLanders.com.

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