Everything you need to know about app-ads.txt

April 7 · Chartboost · 4 Min read
To help ensure a more transparent, fraud-free in-app ecosystem, IAB Tech Lab created the app-ads.txt specification. Think of it as providing caller ID for potential advertisers. Here's more.
The Chartboost blog

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You don’t answer every time your phone rings, do you? You probably check the caller ID first to make sure it’s a call you want instead of some robocall bent on stealing your identity. Even then, caller ID isn’t always 100% accurate. So how can you trust the voice on the other end is who it says it is?

A similar dynamic exists in in-app advertising. To help ensure a more transparent, fraud-free in-app ecosystem, IAB Tech Lab created the app-ads.txt specification. Think of it as providing caller ID for potential advertisers.

What is app-ads.txt?

App-ads.txt is a text file that mobile app developers can add to their website that lists the ad sources — including ad networks and SSPs — authorized to sell their inventory.

Why should publishers use app-ads.txt?

Demand partners crawl developer app-ads.txt files to verify that bid requests are coming from authorized sellers. Proper upkeep of this file helps build publisher trust and inventory reliability in the in-app ecosystem.

PubMatic, a programmatic buyer on Chartboost’s ad exchange explains, “Advertisers that work with buying platforms that support ads.txt and that allow them to target Authorized Digital Sellers can be secure in their digital media expenditure and eliminate the problems associated with buying inventory from unauthorized and unknown counter-parties.”

While this file may help thwart unauthorized developer impersonation attempts (yay!), a publisher’s failure to update its app-ads.txt file could result in lost revenue (boo!). Programmatic buyers may not bid on inventory from any source not included in app-ads.txt files.

In other words, an out-of-date or inaccurate app-ads.txt file leads to lost revenue.

“App-ads.txt is absolutely essential,” says Kaemen Rice, platform account manager at Sonobi, a programmatic buyer on Chartboost’s ad exchange. “As a company built with security at its core, Sonobi relies on app-ads.txt to allow us to continue to work seamlessly in a fully transparent ecosystem that seeks to eliminate fraud while helping to ensure brand safety.”

Open the door to brand advertiser spend

Mobile in-app advertising is expected to account for 20% of budget allocation from media buyers headed into 2023, more than mobile web (17%), connected TV (16%), or desktop (15%). Among Asia-Pacific (APAC) advertisers, 74% invest in programmatic in-app to extend their reach, 72% invest for brand alignment.

As the in-app ecosystem expands into brand advertising, app-ads.txt has surfaced as a necessity. Presently, many app publishers haven’t implemented app-ads.txt, which is causing them to miss out on bids because they haven’t properly authorized their sellers. And with ad budgets typically being drawn up and approved in Q4, the sooner app publishers remove any impediment in the way of brand advertising, the better.

Via The Drum, “Only programmatic, combined with app-ads.txt, can provide the scale and reach to help app publishers attract brand-based demand.” … “It’s time for mobile app publishers to re-evaluate their monetization strategies and adopt the technology and solutions that invite brand spend or they risk being left behind.”

How to set up an app-ads.txt file for your app

  1. Create a developer website
  2. Add your developer website to your app store listings
  3. Set up your app-ads.txt file according to the Authorized Sellers for Apps specification provided by the IAB Tech Lab, including all authorized seller IDs (don’t forget Chartboost!)
  4. Publish your app-ads.txt file in your root domain, as in: https://example.com/app-ads.txt
  5. Verify the content and format of your file — there are a number of helpful tools available, for example https://adstxt.guru/validator/ flags unrecognized domains or incorrectly formatted entries

How to keep your app-ads.txt file current

Chartboost is here to help. Chartboost App-ads.txt Verifier automates upkeep by helping publishers make sure their app-ads.txt files are both discoverable and up to date with all lines required to maximize revenue potential on Chartboost.

Don’t get left behind

Monetize your app, open the door to brand advertising, and prevent revenue lost to fraud. Sign up and start using Chartboost App-ads.txt Verifier today.