Follow Us











Startup Sectors

Women in tech







Art & Culture

Travel & Leisure

Curtain Raiser

Wine and Food


This is a user generated content for MyStory, a YourStory initiative to enable its community to contribute and have their voices heard. The views and writings here reflect that of the author and not of YourStory.

Driving legitimacy in digital advertising with ads.txt

Ads.txt is an initiative by the Interactive Advertisers Bureau (IAB), in order to improve the transparency of programmatic advertising.

Driving legitimacy in digital advertising with ads.txt

Friday December 29, 2017,

5 min Read


The online advertising space is increasingly getting crowded with more and more organizations getting digitalized and vying for customer attention. More businesses are realizing the benefits of programmatic advertising and with this, the programmatic ad supply chain is getting murkier due to several illegitimate inventory sellers exploiting the ad space. Spoofing, where fraudsters imitate legitimate sites to trick genuine businesses into paying for ad spaces which they will never get, is a real and present threat both authentic buyers, as well as publishers, are facing.

So, how do they fight the menace of increasing number of fraudsters? Ads.txt is an initiative that the Interactive Advertisers Bureau (IAB) has come up with, in order to improve the transparency of programmatic advertising.

What is Ads.txt?

Ads.txt stands for “Authorized Digital Sellers”. It is a simple text file which is crawlable by exchangers, buyers, and third-party vendors. The file, which is available in the public domain, helps publishers to declare who is authorized to sell their inventory and helps ad buyers to discern between the legitimate and illegitimate sellers as well as identify which sellers are authenticated to handle the ad inventory for which publisher.

It is not mandatory to use the ads.txt file, but it is recommended as it helps publishers protect their brand from spurious inventory. It also helps publishers gain more buyer spend that may have otherwise gone on the fake inventory. Domain owners who sell their ads on exchanges using their own accounts, a content syndication partnership in which several legitimate sellers represent the same inventory or a sales house or network that sells programmatic advertisements on behalf of a domain owner can implement the text file.

How to implement ads.txt

Implementing an ads.txt file depends on which side of the platform the entity is i.e., whether the supply side or the demand side. In order to implement the file, an ads.txt file needs to be first created by the publisher.

Different SSPs and exchanges may have their own format of creating the ads.txt file. For Google publishers, creating the file is fairly simple. To create a file, publishers should reserve a line for each authorized seller. Each line contains four key fields: the domain name of the exchange, supply-side platform (SSP), header wrapper and similar advertising systems, the publisher’s account ID that is used in transactions, the type of relationship between the publisher and seller whether direct or reseller and the ID of the certification authority. Once this file is created, it needs to be saved as a text file and be placed in the root level of the domain, where it can be viewed publicly.

If the publishers are partaking in real-time bidding, they should transmit the publisher ID and domain through the RTB protocol as this will be useful to the demand side platform (DSP).

On the demand side, when ad buyers get a bid request from a particular publisher, they can quickly check the authenticity of the request by checking if the account ID and exchange match with the ones specified in the publisher’s ads.txt authorized sellers list. They can also obtain the publisher’s ads.txt file by crawling the web and making note of all the sellers that are authorized to sell for the publisher or domain. Through the file, they can also identify whether they are buying the ad space directly from the publisher or an authorized seller.

If they are participating in real-time bidding, they can create a list of authentic sellers and publisher IDs and use the data to cross-reference the list with the data they receive through an RTB protocol. If the publisher ID matches, they can be sure that the seller is allowed to sell the ad space.

How ads.txt helps boost ROI

While adding an ads.txt means that publishers and exchanges will have to spend on developer resources to integrate the text file and to monitor them whenever the files are updated, doing so has long-term benefits, especially in terms of return on investment.

A publisher or a publishing syndicate’s ROI has a direct correlation with its reputation. When illegitimate sellers spoof their domain to create fraudulent transactions, the publisher’s reputation takes a hit and in turn, their revenue too falls. By implementing ads.txt, the publisher is informing the ad buyer, who is allowed to sell ad spaces on their domain, thereby mitigating fraud and improving transparency. Moreover, industry leaders such as Google and sites like Business Insider, Washington Post, Forbes and Gizmodo Media Group as well as giant media buyers are supporting the initiative. In fact, a few leading media buyers are already making it mandatory for publishers to include the ads.txt file in their domain.


Implementation of ads.txt is still in its nascent stages and is yet to see widespread adoption. However, several industry leaders have become early adopters of this formula and ad buyers too are pushing publishers and exchanges for the file’s implementation, as it is a smart way to minimize ad fraud and gain reputation as well as revenues in the programmatic ad market. It may only be a matter of time when adding ads.txt may become a mandatory practice in the programmatic space.