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Elevating inventory quality: app-ads.txt and Open Measurement

, September 6, 2019

As programmatic continues to evolve into the dominant method of buying digital ads, the landscape has grown to be more complex with a seemingly endless cast of publishers and intermediaries. Agencies and advertisers struggle to gain share of attention with their target audience in brand-safe environments at the most efficient price. 

To better serve these buyers and ensure a healthy ecosystem of quality and accountability, We are happy to support two major IAB initiatives: app-ads.txt and Open Measurement (OM).


To help alleviate some of the lack of transparency in the inventory supply chain, the IAB released ads.txt for mobile web and desktop in May 2017. These simple text files are created directly by publishers and live on their websites to specify exactly which parties are authorized to sell their inventory and the exact relationship between them. 

Two years later, advertisers and major Demand-Side Platforms (DSPs) have the ability to target only publishers with ads.txt files on their sites and only sources that are officially listed in those files, with filters down to the relationship type. This helps differentiate quality publishers looking for brand dollars, as well as their close partners that facilitate these buys. Additionally, it gives publishers more control over their inventory in the market, making it harder for bad actors to profit from selling counterfeit inventory across the ecosystem.

Now app-ads.txt is ready to transform the mobile in-app space the same way as ads.txt did for the web. We’re calling all app developers to create and publish their app-ads.txt files to gain adoption and enable brands to start buying based on this standard. 

Today, even though much of the time spent on mobile phones happens in apps, many brands struggle to find quality in-app inventory and spend a disproportionate amount on mobile web. By enabling more transparency and following similar standards to mobile web, publishers can help bring more brand dollars into the in-app and gaming space. In turn, advertisers will be able to more easily target and identify the key inventory sources for mobile in-app and ultimately hit their goals of reaching target audiences at their most engaged moment throughout the day. 

As a publisher, what do I need to do to adopt app-ads.txt for my Unity monetization efforts? The step by step process to adopt app-ads.txt can be found in the IAB app-ads.txt Publisher Advisory. The key steps from that document can be found below:

Step 1: If not done already, the app publisher should make sure that the “developer website” field is up to date in the stores hosting the apps. Such websites will be used by the advertising systems to retrieve the app-ads.txt file. 

Step 2: The app publisher should upload a file named “app-ads.txt” into such website (please see the spec for full detail relocation of the app-ads.txt file), with the list of authorized sellers of their app’s ad inventory per the official guidance. The content of the app-ads.txt file follows the same rules as ads.txt for web with the only exception of subdomain directive – see the spec for details.

The specific fields to be included in your app-ads.txt file can be found in the Settings page of the Operate dashboard. Note that those fields are unique to you as a publisher, and can be copied and pasted directly into your app-ads.txt file.


Please note that Unity’s list of authorized resellers may change over time, and as a best practice we recommend checking the Settings page of the Operate dashboard to ensure your app-ads.txt file is up to date about once a month.

For additional resources on implementation, please see our technical documentation.

Open Measurement (OM)

We are also pleased to share that Unity is certified with the IAB’s Open Measurement (OM) standard. This will enable advertisers who are using a variety of viewability vendors to adhere to a consistent measurement across Unity inventory. For publishers, OM will unlock advertising dollars, particularly from brand advertisers who demand the highest standards of viewability. For publishers to have their inventory OM certified, it will simply require upgrading to the Unity Monetization SDK 3.2 or later. 

One of the challenges often encountered in the mobile ecosystem, and to an even greater degree in mobile gaming, is the misconception of the lack of quality and brand-safe supply. We know this isn’t the case, and that the value and share of attention tied to gaming has been backed by compelling research over the past several years. OM is hugely important for further validating those findings so advertisers can be confident that gaming supply meets or exceeds the standards they have come to expect.

We are in strong support of both of these IAB-driven initiatives. Trust in the gaming ad ecosystem yields higher revenue for publishers, qualified inventory for advertisers, and ultimately a better experience for gamers.

Learn more about our mobile business offerings.

8 replies on “Elevating inventory quality: app-ads.txt and Open Measurement”

For the Open Measurement (OM) certification, the article says that you need to Upgrade to the Unity Monetization SDK, but If we use the Services page in unity, does it automatically get the last version?

If you are on 2018.1+, you can use the Package Manager to get the latest version of the Unity Monetization SDK. If you are using an older version of Unity, then you should download the Unity Monetization SDK from the Asset Store and disable Ads in the Service Window.

There will be no interruption to your ad serving should you choose not to implement the app-ads.txt file on your developer website, but your app may be at risk of inventory spoofing which could result in revenue loss.


From the very first sentence, this article was confusing and made little sense.

It appears to be written in English, yet the meaning is impenetrable at best and unintelligible at worst.

Wibble wibble wibble.

If you’re a developer and this article made no sense to you, that’s OK. Ignore it.
If you’re a developer and article made sense to you, you’ve probably moved on from just using Unity Ads a long time ago.

This article is very confusing, using jargon I guess only ‘monetization experts’ use. Talking about ‘inventory’ and such, what does that even mean? this is online ads. there’s no actual item to have an ‘inventory’ of. Needs to be broken down so laypeople can understand since the target is game developers not ‘advertising gurus’.

I think this is targeted at professionals who will be part of a team sized large enough to have marketing and advertising specific staff in their rosters.

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