Ad Yield Ops 101: Managing Demand Sources Managing ads.txt

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Now let’s discuss how your demand sources need to be managed in your ads.txt file.Let’s begin by covering the basics: What is an Ads.txt File?

It’s important to fully understand what these files are and how they’re supposed to work before you start trying to put one together.

Your ads.txt file is a text file hosted on the root domain of your website. It’s an essential part of the Interactive Advertising Bureau Tech Lab’s ads.txt initiative because it tells advertising buyers which authorized digital sellers you have authorized to sell your ad inventory.

In its simplest form, your ads.txt file is a list of the sellers you have authorized. And if you want to participate in ads.txt — which helps prevent ad fraud and shows buyers that your inventory is high-quality and can be trusted — you have to have one.At its core, the ads.txt initiative is an attempt to map a path in a very complex ecosystem.

The problem ads.txt was designed to solve is ad fraud. But why?

Right around the time ads.txt was released in 2017, one study found that advertisers were wasting nearly $1.3 million USD in programmatic ad spend per day because of a single domain spoofing scam that caused them to buy inventory on duplicated and fake publisher sites.

Meanwhile, for the industry as a whole, experts predicted that digital advertising fraud would cost more than $100 billion dollars annually by 2023. Thus, the need for an industry-wide solution.

Enter Ads.txt.

Ads.txt isn’t a perfect solution — scammers and fraudsters are constantly finding new ways to game the system — but it prevents a host of ad fraud schemes and injects some much-needed trust into the programmatic ecosystem.

As a publisher, you essentially have no choice but to use an ads.txt file if you’d like to participate in programmatic advertising. The concerns you should have is what happens when an ads.txt file is broken.

If your ads.txt syntax isn’t perfect, you risk the possibility of demand sources not being able to serve ads on your website, degrading the competition in your auction, and ultimately losing significant streams of revenue.

Let’s cover the anatomy of a single ads.txt entry.

To actually authorize a seller to sell your ad inventory, you need to include specific bits of information in your ads.txt file. Through automation or manual review, buyers can check these pieces of information in your ads.txt file to make sure the seller is legitimate.

Here are the four key fields to include for each seller:

• The seller’s Name. This is either the business name or domain name of the seller you are authorizing.
• Your ID. Inside the supply-side platform (SSP) or exchange you are authorizing, you will have a unique publisher ID, which you will include in this field.
• Your Relationship. This field defines the relationship between your inventory and the seller you are authorizing. Options here include DIRECT or RESELLER.
• The Seller’s TAG ID. If the seller you are authorizing is certified with the Trustworthy Accountability Group (TAG), you can include their TAG ID to show this certification to buyers. This field is optional.

With the required information in hand, you’re ready to write a first line in your ads.txt file. Then, put each of the four pieces of information described on a single line. Separate each with a comma.

That’s it — you’ve added an authorized seller to your ads.txt file. To add more sellers, it’s a simple matter of lather, rinse, repeat. Starting on a new line of the file, add the four pieces of information for the next seller. Repeat that until you’ve added all your sellers.

What makes it even simpler is that your demand partners should be able to simply provide you the entire line you need to add to your ads.txt entry if you ask.

You are welcome to take a look at Playwire’s ads.txt for an example if you’d like. You can simply find it a www.playwire.com/ads.txt

At the end of the day, an ads.txt file is a piece of code. Like any piece of code you may try to write, it’s absolutely brimming with opportunities to make a mistake. And in digital advertising, a single mistake can cost you an obscene amount of money in lost advertising because your authorized sellers may not register as authorized. That means most buyers won’t purchase your inventory from them.

Outside of the simple code mistakes you could make, there are plenty of ways to mess ads.txt up during the actual implementation process. In other words, even if you think you’re good, you need to make sure. 

There are two basic ways to make sure that your file is built correctly, and they’re both relatively simple:

• First, make sure the file is on your site. If the file isn’t even there, you’re going to have an immediate problem. Fortunately, this one’s easy to check. Simply type your domain name followed by /ads.txt/ and check what loads on that page. It should be your ads.txt file.
• Next, validate that the file is written correctly. If you’re not a professional developer, you may need a little help making sure you entered everything into your ads.txt file correctly. Fortunately, there are of free, reliable ads.txt validators you can use. Simply type “ads.txt validator” into Google, and you’ll see. Most ask you to enter your ads.txt URL or upload the file directly. From there, they return a list of errors in your ads.txt file.

Some of the most common ads.txt file errors that publishers make are:

• Pasting text into the document with formatting (rather than without formatting), which can add extra characters that break the code
• Forgetting one of the required fields for an authorized seller
• Or, improperly adding spacing that breaks the code

Of course, there are tons of other errors that could happen, but those are some of the most common.

Once you’ve built an ads.txt file, you’ll want to add it at the appropriate place on your website. Luckily, we’ve built an extensive Ads.txt guide which provides you instructions for how to add your ads.txt file across the most commonly-used content management systems. Simply follow the link provided in the resources with this module to access the instructions.

Before we go, let’s just cover some of the most important pitfalls you should be aware of when creating and managing your ads.txt file.

Beware that an ads.txt validator will not be able to catch everything for you. For example, a validator will not be able to find out whether each line is properly classified as a direct seller (DIRECT) or reseller (RESELLER). This can make a big impact on your revenue, and mistakes here may pass through a validator because there is no incorrect syntax. 

If you’re working with websites that have one or more subdomains, you may encounter some advanced ads.txt questions. For example, should an ads.txt file go on each subdomain at the top level or just at the top level of the central root domain?

The answer is, it depends. More specifically, it depends on whether you are authorizing different sellers for the various subdomains and your root domain. If you are allowing the same sellers to sell your inventory across your root domain and all subdomains, you only need to upload your ads.txt file to the root domain.

However, if you want to authorize different sellers for particular subdomains, you will need to create different ads.txt files for each subdomain. And in the ads.txt file for your root domain, you will need to identify each of the subdomains using the "subdomain=" variable.

Ads.txt syntax and variables are ever changing. So keep in mind that your file will need to be maintained over time. For instance, the MANAGERDOMAIN and OWNERDOMAIN variables were recently introduced in order to continue to provide clarity across the ad supply chain. Not having newly added variables could impact your revenue, so make sure to stay on top of changes as they come.

To provide you with tactical support in implementing your ads.txt file, we have an entire resource center dedicated to guidance on ads.txt.