Ultimate Guide to Ad Tags

Brock Munro
April 26, 2021
March 20, 2024
Ultimate Guide to Ad Tags

What Is an Ad Tag?

Third party ad tags, also commonly referred to as creative tags or placement tags, are pieces of source code written in either HTML or JavaScript code, which, when inserted into a web page, send a request to the ad server to serve the ad as requested.

Ad tags facilitate the placement of the right ad, to the right user at the right time, all while enabling digital publishers to track ad engagement and measure and record critical metrics.

Ad tags include a wide range of details about the ad units, including their size, format, basic page info, and user data.

Uses of Third Party Ad Tags

Ad tags can be leveraged by a variety of users in the digital advertising ecosystem for various purposes. 

For example:

  • Publishers use ad tags to sell inventory to multiple advertisers and ensure that only relevant ads are shown on their websites. Ad tags allow publishers to serve different ads on one placement, according to the advertiser's targeting preferences.
  • Advertisers receive ad tags from publishers to direct the browser to the ads that comply with the publisher's requirements. The tag will include basic information about the user, such as their location, browser, and carrier.
  • Ad servers who manage the ad serving process from start to finish will encounter ad tags across the entire workflow, connecting publishers and advertisers based on these creative tags.
  • Third-party services (like data management platforms) utilize ad tags to extract user data and create user profiles for use in future campaigns. 

How does an Ad Tag Work and What does The Ad Serving Process Look Like?

An ad tag works in the following way:

  1. Firstly, when a user opens their browser and navigates to a publisher's site, an ad tag code is called, with a signal then being sent to the ad server to find a suitable creative ad unit.
  1. A bid request is then sent to the data provider to get further user details (geolocation, age, and gender) for user targeting purposes. The data provider then returns the request with creative appropriate to the user, ad dimensions, and format.
  1. The ad server then sends this on to advertisers, and a bidding process will occur. Once this is complete, the advertiser will send the creative to the ad server.
  1. Finally, the ad server places the creative on the user's browser to fill the ad inventory space.

Types of Ad Tags

There are two main types of ad tags, synchronous ad tags, and asynchronous ad tags.

Synchronous ad tag: 

As the name suggests, a synchronous ad tag will load simultaneously to the rest of the webpage. When synchronous ad tags are used, if the tag is rejected or another technical issue occurs, this can significantly slow down page load time. 

In this case, the browser will continue to send requests to the ad server, which in some cases may mean the page will fail to load altogether, diminishing the page's user experience considerably. Due to this fact, many publishers prefer to use asynchronous ad tags.

Asynchronous ad tag:

Advertising creative invoked by asynchronous ad tags loads separately to the rest of the web page, offering a significant advantage over synchronous tags. This means the ad tag does not affect the website load time. 

For this reason, Google AdSense uses asynchronous code by default. However, publishers can choose to use synchronous ad tags if they so choose.

What does an Ad Tag Look Like?

Modern digital ad tags are encoded in JavaScript code and consist of a URL from which the applicable browser will request content and info about the placement of the ad.

Synchronous Ad Tags source code will appear like the following example:

<script type="text/javascript">


supp_key = "001b3058ceb2d3effb32e1e548bee49c";

supp_time = new Date().getTime();

supp_channel = "";

supp_code_format = "ads-sync.js";

supp_click = "";

supp_custom_params = {};



<script type='text/javascript' src='//n101adserv.com/js/show_ads_supp.js?pubId=10471'></script>

Conversely, an asynchronous ad tag source code snippet will appear like the following example:

<!-- BEGIN TAG - HEAD -->

<script type="text/javascript">


if(!(window.SuppConfig && window.SuppConfig.ads)) window.SuppConfig = {ads:[]};



supp_channel: "",






(function () {

var sc = document.createElement("script");

sc.type = "text/javascript";

sc.async = true;

sc.src = (location.protocol == "https:" ? "https:" : "http:") + "//n101adserv.com\/js\/show_ads_supp.js?pubId=10471";

var s = document.getElementsByTagName("script")[0];

s.parentNode.insertBefore(sc, s);




<!-- END TAG - HEAD -->

<!-- BEGIN TAG - BODY -->

<div id="supp-001b3058ceb2d3effb32e1e548bee49c-300x250"></div>

<!-- END TAG - BODY -->

The structure of a DoubleClick Ad Tag with the most commonly used key-value pairs will look like this:

Double Click Ad Tag Example

The above ad tag, or placement tag, can be broken down into its various elements to understand how the ad request works.


This part of the URL indicates that in this case, the ad server hosting the ad for the publisher is DoubleClick.


This section of the tag indicates the ad format requested by the ad unit. In this case, it is ADJ which is for image or XML files.


This part of the URL instructs the ad servers - in this case, DoubleClick - to verify whether the 'publisher' is part of the DoubleClick network and whether to proceed with the ad requests.


This information allows publishers control over targeting their users.


This information informs the ad server as to the topic of the ad. An example here may be 'beauty’.


This refers to the subtopic of the ad tag. This allows an advertiser to get even more specific with their ad request. If we follow the above example, the subcategory may be 'skincare'.


This contains the keyword for the required ad creative. Multiple keywords can be used. For example, 'cleanser' and 'moisturizer'.


This variable is the unique value for each ad call on a specific web page. If more than one tile appears with the same value, then the same ad will be displayed on both.


This orders the ad slots on the web browser. If there are two-leaderboard (728×90) ad units on a page, these ad units will be assigning them numbers (like 728×90.1 and 728×90.2).


Quite simply, this defines the size of the ad unit.


A random number is assigned to the ad tag to prevent the browser from showing the same ad rendered from the browser cache. This helps to ensure users see different ad content as they move around the web.

How to Generate an Ad Tag

While there are numerous ad servers and multiple ways that an ad tag can be created, the most common method is through the use of Google Ad Manager.

Web developers can generate ad tags in Google Ad Manager by following these steps:

  1. Firstly, you should log into your Google Ad Manager account.
  1. Next, click on the Inventory tab in the table of contents and navigate your way to the Ad Unit section, which can be found in the left panel.
  1. After selecting the ad unit for which you want to create an ad tag, click Generate Tags.
  1. This will present you with multiple options for the type of tags you would like to use,

including: Google publisher tag, mobile applications, audience pixel tag, accelerated mobile pages tag. Select the tag you wish to generate and continue.  

  1. You can also append the tag with features and key values if required. 
  1. Once this is complete, the ad tag can be pasted directly into the source code of your intended web page.

When it comes to display advertising, understanding ad tagging is essential for publishers, advertisers, and ad networks in the ad serving process.

If you’re making more than $2,000 in monthly ad revenue, contact us today to learn more about how Publift can help increase your ad revenue and best optimize the ad space available on your website or app.

Grow with us

Grow your business with a sustainable, long term partnership. If you're making more than $2,000 in monthly ad revenue, contact us today to boost your revenue with our all-in-one solution.
Laptop screen with web page open

Success Stories