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An IAB-approved text file that aims to prevent unauthorized inventory sales.

What is ads.txt?

Ads.txt stands for Authorized Digital Sellers and is an initiative developed by the Interactive Advertising Bureau (IAB) to counter ad fraud, including domain theft, alleged domain hijacking, and illegitimate inventory arbitrage.

Ads.txt is a text file that publishers host on their web servers, listing companies authorized to sell their ad inventory. Advertisers and media buyers can use this information to validate sellers in a bid request, ensuring they don’t spend their ad budget on counterfeit ad inventory and unauthorized reselling.

Where can we find ads.txt?

The ads.txt file is located in the root directory of a publisher’s website (websitename.com/ads.txt). A publisher’s ads.txt file can be viewed by entering the URL into a browser. Google Ad Manager can also be used to verify if a seller has a valid ads.txt file.

Is ads.txt mandatory?

No, ads.txt is not mandatory. However, publishers are increasingly adopting ads.txt to have more control over who can sell ads on their sites, preventing counterfeit inventory from entering the market.

As more advertisers use ads.txt to validate a publisher’s reliability while protecting themselves from spoofing attempts or fraudulent inventory, we can expect more publishers to implement ads.txt on their sites to build trust and drive ad sales.

Why is ads.txt important?

Digital ad fraud cost advertisers worldwide $65 billion in 2021. Ads.txt helps verify sellers so brands can avoid spending their budget on counterfeit inventory, ensuring more money goes to legitimate publishers.

Ads.txt makes digital advertising more transparent by preventing unauthorized reselling in programmatic advertising. Buyers can verify which supply-side platforms (SSP) are authorized to sell a publisher’s inventory, down to the exact web spot. Advertisers and media buyers can also automate the process of screening dealers based on information in ads.txt files, minimizing the risks of doing business with unauthorized resellers.

Ads.txt helps brands protect their reputation by ensuring their ads only appear on trustworthy websites.

What types of ad fraud does ads.txt help prevent?

Ads.txt is an effective tool for combating ad fraud, specifically domain spoofing and inventory arbitrage. Domain spoofing occurs when a request originates from one site, but the ad is placed on another lower-quality website. With the help of ads.txt, advertisers can identify which Supply Side Platforms (SSPs) are authorized to sell what inventory, thereby avoiding fake impressions and improving inventory reporting accuracy.

Inventory arbitrage, while technically not ad fraud, is a dishonest practice that erodes trust in the industry. It involves a third party purchasing impressions and then repackaging and reselling them at a higher price. Ads.txt discourages inventory arbitrage by listing authorized resellers of a publisher’s inventory. This allows publishers to protect their reputation in the open market and maintain control over their partnerships.

Both domain spoofing and inventory arbitrage deceive programmatic advertising platforms, such as ad exchanges, into believing that high-quality inventory is being accessed, when in reality, the ads appear on dubious websites or are viewed through a covert application designed to generate fake impressions.

The benefits of using ads.txt

Apart from the benefits of cutting fraud, enhancing transparency, and building trust, ads.txt is a user-friendly tool. Publishers can implement an ads.txt file with minimal technical expertise, create and upload one in just a few minutes, and easily maintain it by adding or removing sellers at any time to keep information up-to-date.

The ads.txt process is secure since only website owners can upload and update the file. As a result, publishers can maintain control over their partnerships, prevent unauthorized reselling, and safeguard their reputation.

How does ads.txt work?

Ads.txt is a vital tool in the programmatic advertising ecosystem, serving as a public record of authorized digital ad sellers. Publishers upload the ads.txt file onto their website, confirming domain ownership and verifying partner accounts, such as ad exchanges and SSPs, eligible to sell their ad inventory. Programmatic platforms can also integrate ads.txt files to confirm which publishers’ inventory they are authorized to sell.

The IAB Tech Lab recently released a crawler that can efficiently pull ads.txt files from publisher websites, enabling media buyers and advertisers to validate a large amount of inventory information quickly, compile a list of authorized sellers, and streamline the verification process. When an advertiser receives a bid request from the publisher’s site, it can check the publisher’s account ID against the ads.txt file to ensure that the publisher and inventory are legitimate. If the advertiser can’t validate the publisher’s account, it may choose not to bid on the inventory to safeguard its budget.

For example, each domain publishes ads.txt on their web server and lists exchanges and advertisers that are authorized to sell their inventory, including the publisher’s seller account IDs within each of those advertisers.

How to use ads.txt

To use ads.txt with AdSense, publishers can sign in to their AdSense account and follow the instructions provided. To use ads.txt with Wordpress, publishers need to install and activate the Ads.txt Manager plugin, configure the plugin settings, and add lines to declare each authorized platform or reseller. For instance, publishers can add the following line to declare Google Adsense as authorized: google.com, pub-0000000000000000, DIRECT, f08c47fec0942fa0. It’s crucial to keep ads.txt files current to ensure their accuracy and effectiveness and prevent scammers from exploiting unaudited ads.txt files using the 404bot.

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