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How does Ads.txt work?
April 5, 2024
Sarah Carlson • Content Manager at AUTH 
How Does Ads.txt Work? Navigating trust and transparency in the programmatic landscape
Ads.txt serves as a powerful defence against domain spoofing, as only the publisher has the authority to apply an ads.txt file to their website. This prevents unauthorised platforms from updating the ads.txt file and selling counterfeit inventory.

Here's how the process works:
Starting point
The first step is to correctly integrate the ads.txt file onto the publisher's website. With this, the publisher is able to confirm that they are the owner of the domain and able to meticulously verify partner accounts, including esteemed ad exchanges and SSPs, authorised to represent their valuable ad inventory.
Tip: How can you check sites’’ Ads.txt?
You can directly search whether a site has ads.txt files and display its files by adding ads.txt to the root domain’s end.
Entering the Marketplace:
This allows advertisers with just one click to set up and easily access to a carefully chosen list of reliable publishers and their range of ad inventory.
Sealing the Deal:When a bid request arrives at the advertiser's end, the ads.txt mechanism kicks in. Quickly and accurately, it checks the publisher's account ID (database of authorised publishers) to match the ads.txt file. If the seller account IDs match, this can verify authenticity. If they are not authorised digital sellers or not authorised to sell ads.txt , the process pauses, allowing the buyer to avoid risks.