Online advertising fraud has had a substantial negative impact in the digital advertising industry. It affects both advertisers and publishers. Advertisers are losing money paying for impressions and clicks which aren’t seen by real people, lowering their return on investments. Publishers are receiving less revenue due to bad actors falsifying and gaming the market. What can we do to help the industry fight back? In this article we’ll talk about app-ads.txt and the problems it intends to solve.
What is app-ads.txt?
App-ads.txt is a simple text file which app developers upload to the root of their developer website listed on their app store landing page. This text file lists the Supply Side Platforms (SSP) which you have authorised to sell your ad inventory.
App-ads.txt (Authorised Sellers for Apps) is an extension to the ads.txt (Authorised Digital Sellers) standard released by the Interactive Advertising Bureau Tech Lab. Whereas ads.txt was originally designed to combat against web ad fraud, app-ads.txt extends this to support mobile apps.
How does app-ads.txt work?
Online ad exchanges are similar to marketplaces. There are buyers and there are sellers. In the ad world they are known as advertisers and publishers. The product being sold in this marketplace is ad space on a website or app. Ad space is also commonly referred to as inventory. Ad inventory is valued by the amount of impressions (ad views) or clicks an advert receives.
When using app-ads.txt, a Demand Side Platform (DSP) that is looking to buy ad inventory scans the app-ads.txt file of the publisher to verify which Supply Side Platforms are authorised to sell that app’s inventory. If the SSP is authorised the DSP goes ahead with the purchase. This practice will help defend against bad actors who disguise ad inventory as that of another premium app, therefore reducing advertising fraud.
Online advertising fraud
Online advertising fraud is a huge problem which has to be addressed and eliminated. The exact scope and scale of it is unknown and impossible to calculate but it is a plague which affects both advertisers and publishers. According to some estimates it cost the industry billions each year. Here is a list of some of the commonly known threats the web and mobile ad industry face.
Types of online ad fraud:
- Ad Stacking - This is a type of Impression fraud whereby multiple ads are layered on top of each other. One ad will be visible whilst racking up multiple impression for the other ads stacked underneath.
- Click Fraud – This can be through the use of bots, or click farms where low paid workers in third world countries are paid to click on ads.
- Conversion Fraud – This is when fraudsters stuff users with their cookies so that when a user registers an affiliate conversion, the swindlers get paid instead of the publisher.
- Ad Injection – This is where ads are replaced by malicious scripts or malware for ads that aren’t intended for the original publisher’s inventory.
- Inventory Spoofing – This is when publishers or ad agencies distort ad meta data and performance statistics with intent to pretend to represent a premium publisher.
Which problem does app-ads.txt solve?
The type of ad fraud app-ads.txt intends to solve is inventory spoofing. Implementing app-ads.txt prevents deceitful publishers and middlemen resellers from selling counterfeit ad space based on the reputation of popular apps. App-ads.txt allows the buyer of the ad space to verify that the seller or reseller they bought the ad-space from was authorised by the app publisher. This way they don’t end up buying spoofed or fake ad space. Therefore, preventing premium ad inventory from ending up on unknown apps.
Inventory spoofing is most prevalent in programmatic advertising platforms and real-time bidding (RTB) ad exchanges where your app meta data and ad inventory are manually declared. As a developer, using app-ads.txt ensures that your digital ad inventory is only sold through direct sellers and resellers which you authorise and trust.
How to create app-ads.txt for AdMob
- Create a txt file and name it
- Log into your AdMob account, go to Apps > View all apps > app-ads.txt tab.
- Click How to set up app-ads.txt and copy the following code snippet which pops up exactly into your app-ads.txt file created earlier.
- Host this text file on the root domain of the developer website listed in your Google Play or App Store app description landing page.
- Ensure that the file is publicly reachable e.g. on
If you do not own the root domain you will need to contact your webmaster and ask them to upload this file. If one already exists, ask them to appended the contents of your app-ads.txt to their app-ads.txt. click here for more information.
Click here for more information implementing app-ads.txt.
App-ads.txt example file
- Field #1 - The domain name of the advertising system. This is the operation domain name of the ad exchange or SSP.
- Field #2 – Publisher’s Account ID. This is the seller account id e.g. your publisher id from Google or Apple.
- Field #3 - Type of Account/ Relationship. This is the business model how the exchange deals with your inventory e.g. Direct or Reseller.
- Field #4 (optional) - Certification Authority ID. An ID that uniquely identifies the advertising system within a certification authority e.g. the Trustworthy Accountability Group TAGID.
This is how an example App-ads.txt file looks like:
google.com, pub-0000000000000000, DIRECT smaato.com, 0000000000, DIRECT, 00x0000x000000x0 unity3d.com, 00000, DIRECT adcolony.com, 000000000000aaaa, RESELLER, 0xx000x0xx0x0000 appnexus.com, 0000, RESELLER
Check out the full specification here.
Should I add an app-ads.txt file?
App-ads.txt is not mandatory at the time of writing this article but it is highly recommended because it can help buyers identify ad inventory fraudsters. This should help reduce the of amount money being siphoned away on counterfeit inventory, allowing advertisers spend to go towards legitimate ad space.
Ad fraud is a massive problem which requires an industry wide effort to solve. The more developers implementing counter fraud measures like app-ads.txt the cleaner the advertising ecosystem becomes. In-turn advertiser confidence is boosted and publisher revenue increases for legitimate developers. Implement app-ads.txt now and share this article with a developer or advertiser.