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Several technologies help online advertisers and publishers, making selling, buying, and delivering ads easier.  The Ad servers are a critical part of digital advertising. Because of the array of advertising technology solutions, the role of the ad server is often confused. Let’s look at what is an ad server and the top solutions.

What Is an Ad Server?

An ad server is a technology that allows organizations to manage, serve ads to usrs visiting digital properties. An ad server is a technology that decides, in real-time where to sere the ad based on the relevance of the target site. Ad servers store the ads, select in real-time which one is the best for a specific digital property, and then serve it. The entire process is done in the time page downloads.

How Does it Work

Besides deciding what ads to show on a website, ad servers have other functions. For instance, the tracking and collecting data of the ads. An ad server is involved in every step of the inventory buying and selling. Here are the steps of how it works:

Step 1. Ad tags

Ad tags are small programs inside the ad unit that are placed on the website to display the ads. They act as placeholders for the ads. These tags hold the details of the size, format, and other requirements.

When a user visits the publisher’s site, the ad tag calls the ad server. The ad server then shares the details of the ad unit available with the demand-side platform.

Step 2. Selecting the ad

Next, the demand-side bids on the ads. The ad server receives the bids, compares them, and chooses the highest-paid and most relevant ones.

Step 3. Calling the ads

Publishers and advertisers usually have different ad servers. Once the ad server selects the winning bid, the advertiser’s ad server sends it to the publisher’s ad server. The publisher’s ad server serves the ad on the available ad unit.

Used by
Primary value
Creative management and tracking of the ads as they appear on publisher's website. .
Implements real-time creative optimization and creative rotation via independent tracking metrics.
Publisher side
Ad operations, end-users in a self-serve platform.
Serve the ads that appear in the digital properties.
Monetization of digital properties. Storage and management of the ads appearing on their site or app.

Ad Server Types

Ad servers can be categorized according to the side it attends, if it is a first-party or third-party solution, if it is hosted or open-source.

First-party Ad Server

First-party ad servers are hosted on the publisher’s server to serve advertiser’s ads.

How do first-party servers work? 

This process needs to be repeated across publishers. So, what do advertisers do when they need to measure their campaigns across multiple publishers? Use a third-party server.

Step 1: The user visits a website. The browser sends a request to the publisher’s web for the page’s contents.

Step 2: The publisher’s server returns the information by rendering the page’s contents.

Step 3:The publisher’s ad server gets an ad request from the demand’s ad server to fill the available slot on the page.

Step 4:The ad server chooses and displays an ad based on the information about the user and the site.

Third-party Ad Server: 

It helps advertisers or ad agencies to manage, store and track ad campaigns across multiple publishers.

How do third-party ad servers work?

Third-party ad servers work differently from first-party ad servers.

Step 1: The user visits a website and the browser requests from the webserver about the page’s content. 

Step 2: The publisher’s ad server start rendering the page content. The publisher’s ad server chooses the best ad for the slot.

Step 3:The publisher’s ad server sends back the code inserted in the ad slot connecting it to the advertiser’s ad server.

Step 4:The ad markup (the code), registers an impression.

Step 5:The advertiser’s ad server sends the code to the publisher’s website. The website then displays the ad.

Open Source Ad Servers

An open-source ad server is an ad serving script that you can download from a third-party server and host on your own servers. The code is free, but you need to maintain the service and pay the server costs.

Why Do You Need an Ad Server?

There are many benefits for using an ad server for publishers: 

  • Helps monetize your digital property: By optimizing the bids on ads, you maximize your digital property yield. Publishers can make more money by selling ads without the hassle of negotiating directly with the advertiser.
  • Improves e-commerce features: With an ad server, you can integrate sponsored listings into your e-commerce site. These sponsored listing ads enhance the user experience and increase your website’s revenue.
  • Promotes internal content: You can use an ad server to cross-sell products across different digital properties, therefore expanding your revenue possibilities.

Best 4 Ads Servers for Publishers

Now that you know what is an ad server and the advantages of using one, let’s evaluate the best options and an alternative: 

  1. Google Ad ManagerGoogle Ad Manager


It is the most widely popular in the market. Google Ad Manager offers a range of features including an Ad Exchange allocation, monetization options, and more. Management and reporting are fairly simple.

Google Ad Manager has two versions: the small business version, which is free. The enterprise erosion (paid) offers more features.

2. Smart Ad Server

Smart Ad Server

Smart ad server enables publishers to run programmatic or direct campaigns. They offer several digital formats and for screen sizes. The platform offers monetization functions via a unified auction process. Some of the features include cross-platform trafficking, advanced targeting, flexible ad building, and granular reporting.

3. Kevel

Kevel Ad server

Kevel API offers users the opportunity to build custom online ad serving platforms for themselves. With Kevel API, a company can build an ad server and get campaign control, raise revenue, and improve reporting capabilities.

Their white-label product offers organizations the chance to have a working publisher ad server.

4. Verizon Media 

Verizon ad server builder

This ad server offers publishers access to management and ad serving functions. You can manage campaigns for multiple types like display, video, and mobile. It is a managed service that includes forecasting, cross-screen monetization, programmatic ads, and inventory management.

Best Ad Server Alternative

CodeFuel- The best ad alternative

Leveraging an ad server can give you a lot of advantages, but if you want to monetize your digital properties, an all-in-one platform is what you need.

Unlike an ad server, CodeFuel offers a complete monetization solution designed for publishers. Its goal is to maximize the publisher’s yield by leveraging AI and machine learning to show highly targeted ads based on the user’s intent.

 Ad Server Vs. Ad Networks

An ad server and an ad network are different solutions. But many people, including marketers, are often confused between both terms. Lets review the pros and cons of each one:

Ad Server Pros

  • Flexibility: It provides flexibility in managing multiple ad campaigns.
  • Performance: Ad servers automatically select the ad  performing the best. / Therefore, it maximizes the publisher’s revenue by serving continuously.
  • Multi-level targeting: The ad servers allow publishers to target the audience related to the ad campaign goal. Ad Servers provide multiple targeting options.

Ad Server Cons

  • Long setup time: Most ad servers require time and effort to set up websites or ad units.
  • Long load time: Many servers cause pages to load longer. When this happens, the ad slot will show empty.
  • Ad serving cost: They can be expensive for small publishers since most solutions require payment for premium features. Publishers usually need to pay extra to run the ad campaigns effectively.

Ad Network Pros

  • Reach and scalability:  Ad networks drive efficiency and allow advertisers to reach a wider audience.
  • Highly targeted options: Ad networks offer the possibility to target by specific type of content, device, location, demographics, and even behavior.
  • Flexibility: Usually, the ad networks pricing is more flexible than ad servers. Ad networks may have different pricing models, like CPC or CPM. .
  • Time-savings: Ad networks are faster to install and use than ad servers. Therefore, for small publishers, they are a better option.

Ad Network Cons

  •  Lack of transparency: Some ad networks give a list of their publishing partners, but most don’t let advertisers know where their ads will run.
  • Prices can be negotiated: In some cases, companies can negotiate a price in bul for a certain amount of impressions. Other ad networks only focus on real-time bidding.

What are the features of an Ad Server?

While there is no ad server solution that includes all features, here is a list of the most commonly employed by top vendors.

Targeting features

  • Location on page
  • Subcategories
  • Repeat once for the same user a day
  • Filter by time, location, gender, age.

Ad Delivery Features

  • Ad capping
  • Goal optimizations
  • Priority waterfalls
  • eCPM auctions
  • Ad pacing

Ad management

  • Hosted UI for managing the campaigns
  • API for creating and managing ads
  • Flexible ad unit options
  • Campaign scheduling
  • Macros

Other features

  • Tracking and reporting
  • Third-party tag enablement
  • Compliance
  • Multiple server locations

How to Start Integrating an Ad Server?

You have four main options:

1. Building an Ad Server

If you have a great engineering department, you can build your ad server:


  • Customization. You can build whatever you want and integrate it into your existing content.
  • There is no fear of third-party changing prices.


  • Time-intensive and expensive.
  • It requires maintenance and optimization.

2. Build it with third-party infrastructure

You can use an ad serving API and build your ad server quickly.


You can customize an ad server faster and cheaper than building it from scratch.


It is still more time-consuming than leveraging a ready-made platform.

3. Self-host it

This involves using an open-source ad server.  


You don’t need to pay a monthly vendor fee and access an ad server architecture.


You still need to do engineering work to host the server. These tools are not very customizable.

4. Use a hosted third-party platform.

There are a lot of SaaS ad server solutions, where you pay a subscription. These boxed solutions can work by placing a Javascript tag or code, and they usually have their own UI to manage your campaigns.


Implementation is very fast. Price is usually also more competitive than other choices.


Most solutions are JavaScript-based, which can increase the load time of your page. Since they are boxed solutions, the customization options are limited.

What Is the Google Ad Server?

Is an ad server and platform that combines the best features of the DoubleClick Ad Exchange and the DoubleClick for publishers into a single account. Google provides ad serving capabilities to help publishers optimize their ad revenue and monetize their digital properties.

To use Google Ad manager, you need a Google Ads account. Users can use GAM for free until a specific number of impressions.

The history of Ads Servers

Before ad servers existed, the exchange between advertisers and publishers was direct. Advertisers and publishers would meet and negotiate the ad placements. To display ads on a publisher’s site, advertisers sent insertion orders (IO) to the publishers’ sales team to display ads on the publisher’s site. These orders aligned with the campaign terms, goals, and payment.

In 1995, the first ad server was launched by a company called FocaLink Media Services. The company later was acquired by Google. By 1996, Yahoo started displaying search ads, and Google will launch AdWords in 2000. It was the beginning of a very interesting industry.

But it was not until 2007/2008 that real-time bidding is introduced to allow advertisers to buy impressions on websites via real-time auction.

    • What are the main functions of an ad server?

      • It stores and manages ad codes
      • Set the tracking criteria for ad campaigns
      • Track ad performance
      • Measure the reach of a campaign


What are examples of ad servers?
The most popular hosted ad servers are

      • Kevel
      • OpenX Ad Server
      • AdButler
      • Revive Ad Server.

Why should you use an ad server?
Ad servers help all participants of the online advertising environment reach their goals. It helps publishers to monetize their inventory better. It also helps advertisers to acquire ad units more efficiently.

What are the main functions of an ad server?

  • It stores and manages ad codes
  • Set the tracking criteria for ad campaigns
  • Track ad performance
  • Measure the reach of a campaign

What are examples of ad servers?
The most popular hosted ad servers are

  • Kevel
  • OpenX Ad Server
  • AdButler
  • Revive Ad Server.

Why should you use an ad server?
Ad servers help all participants of the online advertising environment reach their goals. It helps publishers to monetize their inventory better. It also helps advertisers to acquire ad units more efficiently.



Ad servers can be the best ally for optimizing advertising for publishers. Hopefully, this page can help you understand when to use them, the best solutions, and alternatives. While ad servers may seem essential, consider leveraging a monetization platform for a more comprehensive alternative. Learn how CodeFuel provides maximum monetization yield to publishers while enhancing the user experience. Sign up today.

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