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Ads.txt: Implementation and FAQ

Where Does Your Ads.txt File Stand?

Sovrn is committed to ensuring that your advertising inventory is highly valued by our buyers, and Ads.txt is a huge part of that.  

As the industry evolves, we all adapt at different speeds. As always, we are here to help, regardless of your pace. However, over 50% of Sovrn’s demand is changing buying behavior based on Ads.txt. This is revenue you do not want to miss out on!  

Choose the option that best explains your current ads.txt situation and follow the steps to complete your process.
If you are starting from scratch, we will walk you through these four steps. Feel free to jump to the one you are looking for.

    1. Ads.txt file creation
    2. Proper formatting instructions
    3. Sovrn implementation instructions
    4. Organization suggestions
    Ads.txt File Creation
    1. Open or download a FTP service
      • What is FTP? File Transfer Protocol is simply an easy way for you to transfer files from your computer to your website.
      • Sovrn recommends FileZilla. It is free, open source, and easy to use.
        • Is FileZilla the required FTP client? Nope! As long as your ads.txt page has a file path resulting in domain/ads.txt, how you go about creating that file is completely up to you. Make sure to follow the format specifications carefully but feel free to stick with the creation method of your choice. The following instructions outline one of many options available to you.  
    2. Create a txt file with your ads.txt information.
      • To create a text or txt file, all you need is a text editor or a word processing program like Microsoft Word, WordPad, Notepad, or Atom. When saving the file, simply select the .txt or Plain Text file format option.
      • What ads.txt information? Don’t worry, we cover that in steps two and three! For now, feel free to throw in some placeholder information like the example image below.
      • Save the file in an easy-to-locate folder on your computer.
    3.  Connect to your website using FTP
      • Open your FTP client, downloaded in step a, and login to your domain’s FTP using your web host credentials.
        • Web host credentials? They are supplied by your hosting service (HostGator, GoDaddy, etc.) and listed as FTP accounts. You received these credentials via email when you signed up for your website.
    4.  Locate your txt file within the directory of your computer.                 
    5.  Select the txt file, then drag it to your website’s home directory.
      • This will create a path of the same file name after your domain – ie
    6. Open the internet browser of your choice and ensure ads.txt is displaying correctly by visiting your new webpage.


    • What is ads.txt?
      • Ads.txt is an initiative from the Interactive Advertising Bureau Tech Lab (IAB) to promote and improve transparency in programmatic advertising. It’s an easy way for publishers to clearly indicate to buyers who is authorized to sell their inventory.
    • How does ads.txt actually work?
      • The Ads.txt file is a public declaration by a publisher to say who the publisher authorizes to sell advertising on the publisher’s site. Once the Ads.txt file is posted, advertisers or DSPs acting on behalf of advertisers can scan sites and catalog the Ads.txt information for future use.
      • When an advertiser gets a bid request, they can check their catalog of Ads.txt information to verify that the bid request is coming from an authorized seller.
      • In addition, and if an advertiser wins a bid request, the advertiser will only pay the authorized seller, thereby further reducing the incentive for fraudulent actors to spoof domains.
    • Why can’t a spoofer just look at a site’s Ads.txt file and use that information?
        • The Ads.txt file references a publisher’s Account ID and not the fraudster’s, preventing the fraudster from getting paid for spoofing a site. This eliminates the incentive for fraudsters to spoof someone’s content.

      • On the Demand side, partners would see that the ID making the request differs from the ID in the ads.txt file and the request would be considered invalid.
    Proper Formatting Instructions
    1. Make sure to properly format your ads.txt information before adding it to your txt file. Improper formatting will render the file ‘unreadable’ and invalidate it. Full documentation can be found here.
    2. File Format and Syntax Requirements
      • The core syntax is a comma or space separated format with three defined fields (outlined below) and one record/partner per line.
      • No field should contain an embedded field separator (tabs, %, whitespace, etc).
    3. There are three required fields for each partner entry;
      • Domain Name of the Advertiser (Required)
        • The operational domain of your exchange partner
      • Seller Account ID (Required)
        • The identification number associated with your account for this partner
      • Type of Relationship (Required)
        • The kind of relationship that your partners have with the selling of your inventory. There are two options here.
        • DIRECT indicates that the publisher has a direct business relationship with the SSP or exchange. There are no skips or jumps between the publisher and the SSP when selling inventory.
        • RESELLER indicates that the publisher has authorized this entity to sell inventory on their behalf, through another party.
      • Certification Authority ID (Optional)
        • An ID that uniquely identifies the advertising system within a certification authority.
    4. Want to make sure that everything is properly formatted and ready to go? Check out AppNexus’ verification tool here.


    • Will it work if a publisher puts ‘www.’ before each line?
      • No! This is the most common way that publishers incorrectly implement Sovrn in their Ads.txt file. This leaves the publisher’s inventory vulnerable to digital advertising fraud.
    • Why do ads.txt errors matter?
      • Ads.txt errors can result in missed opportunities during the bidding process. More and more DSPs are introducing Ads.txt as a targeting criteria, and if a typo interferes with your authorization of a certain supplier, your inventory won’t be sold, or it will be sold to the next highest bidder.
    Sovrn Implementation Instructions
    1. The very best way to receive the appropriate and most up to date Sovrn ads.txt information is to reach out to us directly. Your Sovrn representative will have exactly what you need but you are also welcome to email
    2. The file will include two DIRECT Sovrn entries (examples found in the ads.txt file creation instructions above) and a list of RESELLER’s.


    • Does Sovrn resell my inventory?
      • Yes, Sovrn can resell your inventory in certain situations. Sovrn does this to increase the yield and revenue for its publishers. For example, there are some advertising campaigns with specific criteria like volume, viewability or GEO. Sovrn will sometimes resell a publisher’s inventory in order to meet these specific advertiser criteria.
    Organization Suggestions
      1. As many publishers have come to realize when building out their ads.txt files, entries can start to pile up and things get unorganized quickly. Below are two main suggestions, within the proper formatting requirements, to help you keep your sanity.
        • Break out all of your partner entries.
          • Differentiate each partner entry so they are easier to find in the future. When partners make changes to their DIRECT and RESELLER entries it is helpful to know each partner’s location within your file.
        • Space out and label each grouping.
          • Put a space between each partner grouping to make distinctions clearer.
          • Label each group with the name of the associated partner to better track which grouping belongs to whom.
            • NOTE: Make sure to properly comment out your label of choice. This formatting requirement is a ‘#’ character.
          • This is a great example!

    Have questions? Want to know what other publishers are doing? Join the discussion!

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