What is Ads.txt and How to Implement It in 2024?

When there’s money to be made, there are fraudsters looking to take advantage.

That is why the Interactive Advertising Bureau (IAB) Tech Lab created ads.txt to help fight against fraudulent activities in the digital advertising industry.

But what exactly is ads.txt, how does it work, and how do you implement it? Let’s dive in.

What is Ads.txt?

Ads.txt, or Authorized Digital Sellers, is a publicly available record of authorized digital sellers for a publisher’s inventory.

Ads.txt was developed in 2017 to provide transparency and authenticity to the programmatic advertising ecosystem, as it ensures that advertisers are buying inventory from legitimate publishers and authorized sellers.

Ads.txt is a simple text file that is hosted on the root level of the publisher’s domain, containing a list of authorized sellers for each ad exchange that the publisher uses.

To access someone’s ads.txt, simply type: www.websitename.com/ads.txt

Why is Ads.txt Needed?

Ad fraud is a widespread issue in the digital advertising industry, where fake ad impressions and clicks are generated by bots or fraudulent websites.

This creates a situation in which publishers lose money because fraudsters sell mislabeled ad space and fake traffic under the publisher’s name.

Fraudsters are able to mislead buyers because the latter usually rely on the legitimate transition of their purchased URLs by publishers. However, there is no ultimate way to confirm that the passed URLs represent the actual impression moving across exchanges. Also, buyers are not able to identify who is selling those impressions. 

Even though the URL and Publisher ID are included in the impression from the Open RTB protocol, buyers still can’t identify the publisher ID owner. This, along with the problem of validating the information sent in the RTB bid request, leaves space for counterfeit inventory.

Ads.txt is used to fight against this ad fraud and counterfeit inventory.

Benefits of Ads.txt

The benefits of ads.txt are numerous. Here are a few of the most significant benefits:

Reduces Ad Fraud

Ads.txt helps to reduce ad fraud by ensuring that ad buyers purchase inventory from authorized and legitimate sellers.

Increases Transparency

Ads.txt provides transparency and clarity in the programmatic advertising ecosystem. It helps advertisers to trust the inventory they are buying and ensures that publishers receive proper credit for their inventory.

Improves Brand Safety

Ads.txt helps advertisers to protect their brands from being associated with low-quality or fraudulent websites.

Gives Publishers More Control

Ads.txt gives publishers more control over who is selling their inventory and ensures that their inventory is sold at the correct price.

What Information Do You Need to Create an Ads.txt?

The process of uploading ads.txt is quick and straightforward. It’s similar to robots.txt file installing, which appears in the majority of websites.

Also, there are no restrictions which websites can have ads.txt. The most important aspect of ads.txt is that the information is accurate and includes the necessary details. 

The below image shows the data about the inventory authorized sellers that should be included in the ads.txt list.

Mandatory sections:

• Partner1 is the domain name of the authorized seller or reseller of the publisher. 
• 678910 is the seller or reseller account ID. You can get it directly from the seller. 
• DIRECT or RESELLER indicate the type of relationship between a publisher and a seller/reseller. Direct relationship means publishers cooperate with the vendor without intermediary parties. Reseller relationship includes intermediary vendors.

Optional sections:

• g45tg4e is the certification authority ID or the unique identification code of the advertising system.
• #banner shows what kind of inventory the publisher sells.

As you see, the ads.txt file includes all the important information about the publisher. This means that if the programmatic buyer receives an offer bid, they can validate the seller information. Particularly, they can crawl the publisher’s ads.txt to see whether the reseller is included in the list and compare the data.

Therefore, if all the websites have an accurate list of their vendor partners, and all the buyers check the list before making a purchase, fraudsters have no chances.

How to Add Ads.txt to Your Website

First, it’s important to note that your ads.txt file should always be uploaded to your primary domain AND all the subdomains that you are monetizing.

Here are five different ways you can add ads.txt to your website:

Use a Simple Text Editor

The process of adding ads.txt with the text editor is similar to that of any other document. For that, follow the basic rules.

• Create the text
• Input the above-required data in the mentioned order
• Save it in .txt format
• Upload it to your website as a new page at www.website.com/ads.txt. 

Use a WordPress Plugin

Install an ads.txt manager plugin on your WordPress-managed site. After installing, click Settings > Ads.txt on the left panel. Place the required data and press Save. 

Use Google AdSense

If you have an AdSense account, click on Sites > down arrow > Create an ads.txt file > Download. After these steps, your ads.txt will be downloaded automatically. You can further upload it to the site’s root directory. 

Use Google Ad Manager

In your Google Ad Manager account, select Admin > Ads.txt management> Web ads.txt > Create an ads.txt file > publish ads.txt to root domain.

After those steps, you will have your vendors list generated by Google Ad Manager. Edit it if needed and copy/paste the list to your created ads.txt. You can also download it and upload it to the root directory later. 

Let Adnimation Do It for You

Publishers who partner with Adnimation, a Google Certified Publishing Partner (GCPP), enjoy remote management of their ads.txt file.

This service is a part of the technology and monetization service that we at Adnimation offer. This way, you don’t need to worry about keeping the file up to date and it’s always accurate. 

What Happens if Your Ads.txt Is Implemented Incorrectly?

If your ads.txt file is implemented incorrectly, you will generate less revenue because programmatic buyers will be less willing to purchase your inventory.

Additionally, incorrectly implemented ads.txt files can also negatively impact your website’s overall user experience, potentially leading to a decrease in traffic and engagement.

What to Avoid When Creating an Adx.txt File

Before listing the main things to avoid when creating the file, keep in mind that you create the list for the web crawler robots. This means robots should be able to easily access and read the information.

These are the main mistakes that cause poor ads.txt performance:

Too Many Rows

In the best case scenario, demand side platforms (DSPs) will only read and consider 200-300 rows of your ads.txt. Worst case, they will ignore it all together.

If you have too many vendors, it’s better to include only the main ones in the list. 

Second-Level Selling Partners

If your ads.txt contains too many resellers, it can raise red flags among DSPs. It’s better to have only unique partners and not second-level sellers.

Bad Syntax

When implementing ads.txt, make sure to keep a good syntax: avoid typos and keep all the information in one line.

A good syntax is the usual structure of the ads.txt robots are “taught” to identify. If they see the same vendor’s information broken in two, three, or more rows, the robots won’t read the file properly.  

Ads.txt Analyzer

For professionals, we recommend adding the Chrome extension Ads.txt Analyzer, which provides easy access to any website’s ads.txt file directly from the browser.

You could install the Ads.txt Analyzer extension here.