What is app-ads.txt?

Why you need to adopt app-ads.txt now to ensure increasing mobile app revenue long term

There has been widespread adoption of ads.txt in the last few years since the Internet Advertising Bureau (IAB) launched the ads.txt initiative in 2017. We can see why publishers are getting on board.

Data from Pixalate’s Trends Report Q4 2018 reveals sites with ads.txt had 23% less invalid traffic (“IVT”) than sites without ads.txt. However, in the same report, it noted that mobile in-app programmatic advertising had an increased IVT rate of 23%. Yikes!

It’s only natural then as more brands dedicate ad budgets to in-app advertising, the IAB has extended ads.txt for OTT and mobile apps. App-ads.txt, or Authorized Sellers for Apps, is the same standard ads.txt extended to apps and OTT or “Over The Top” media. The app-ads.txt file allows mobile app publishers to publicly list who is authorized to resell their advertising inventory.

In this article, we’re going to dive into specifically what apps-ads.txt is, how it works, why it’s important for app developers and the advertising industry as a whole and how it will help boost in-app revenue.

But first. Refresher. What’s ads.txt again?

Ads.txt was launched in order to bring more transparency to the programmatic ecosystem, prevent unauthorized inventory sales and help combat ad fraud and domain spoofing.

Ads.txt is a simple text file that allows digital publishers to authorize who can sell their ad space. It’s a flexible and secure method for publishers and distributors to publicly declare companies they have authorized to sell their digital inventory. Take a deeper dive into ads.txt in this article.

Which players have already adopted ads.txt? According to FirstImpression.io, 43% of the top Alexa 1000 domains have now implemented ads.txt while the top 3 advertising systems using ads.txt are Google with a 94% share followed by Rubicon Project with 84% and AppNexus with 83% shares.

Now that we got that cleared up. So, what’s app-ads.txt?

App-ads.txt is an extension of ads.txt for mobile in-app and OTT advertising. Just like web publishers, app publishers use an app-ads.txt file to list authorized digital sellers of their mobile ad inventory, while DSPs (Demand Side Platforms) use it to validate that inventory is coming from an authorized source. Programmatic ad buyers can check these lists to make sure that a company claiming to offer an app’s inventory is actually able to sell that inventory.

The IAB is encouraging app publishers, buyers and app stores to implement the new app-ads.txt guidelines and remove misrepresented app inventory from programmatic supply chains. You can read IAB’s most recent app-ads.txt specification documentation for all the juicy stuff.

How does app-ads.txt work?

Any DSP looking to bid on app inventory can scan the app-ads.txt file on a developer’s website to verify which ad sources are authorized to sell that app’s inventory. Only bid requests from ad sources listed on the file and authorized by the app developer are accepted.

App developers create an app-ads.txt file and publish it to their own developer domain listed in the App Store and/or Google Play store.

How do you implement an app-ads.txt file?

To set up an app-ads.txt file, there are three basic steps to follow:

Step 1: Developers must first provide a website URL in-app store listings.
This website will be used by advertising platforms to verify the app-ads.txt file.

Step 2: Reach out to your ad sources.
Get in touch with your direct ad sources and ask for their app-ads.txt line, according to the IAB’s structure.

The app-ads.txt file must include the ad source domain name, the publisher ID, the type of relationship (direct or reseller), the ad source ID.

Example: adnetworkdomain.com, publisher-ID, DIRECT, 1234

Your direct demand partners should be listed as “direct.” If your partners are using third-party resellers to sell your inventory, those providers must be listed as “reseller.” Either way, don’t add a provider to your app-ads.txt file unless you have a direct relationship with them.

Step 3: Publish an app-ads.txt file and upload it in the root domain of your website.
Create an app-ads.txt file in Notepad listing out all the lines you received, and save.

Create and publish the app-ads.txt file in the root directory of your site

In this file, include all authorized publisher codes for the networks your app sells through in the file. Upload the file in the root of your domain website.
Example: https://www.example.com/app-ads.txt

How can app-ads.txt benefit your app?

Ads.txt has become the gold standard for combating ad fraud on websites and ensuring quality inventory. Providing that security for apps is the next natural step in the programmatic ecosystem.

For app developers there are two obvious benefits:

  1. You will earn more revenue over the long term. More DSPs that adhere to app-ads.txt won’t purchase inventory missing the app-ads.txt file meaning if you don’t have app-ads.txt, you risk eventually being removed from a DSP’s targeted apps and media.
  2. Fight ad fraud. There are bad actors out there who may falsify apps that impersonate legitimate apps, misleading DSPs to spend brand budgets on fake inventory. Legitimate developers end up losing out on ad revenue that was originally intended for them. App-ads.txt blocks unauthorized developers from these types of impersonations and minimizes instances of fraud that ultimately hurt developers’ bottom line.

Additional App-ads.txt Resources

Want to read up? Here are some extra resources that explain more about ads.txt and app-ads.txt:

IAB Tech Lab – Ads.txt Authorized Digital Sellers
IAB Tech Lab – How to create and post an ads.txt file
IAB Tech Lab – Authorized Sellers for Apps (app-ads.txt)
IAB Tech Lab – ads.txt Specification Version 1.0.2


Implement your app-ads.txt now!

Sign up here for free to host your app-ads.txt file on our domain. Then provide the website URL in the app store listings on Google Play or the App Store.