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Ads.txt and Sovrn Ad Exchange

Learn how to create, maintain, and update your ads.txt file to avoid missing out on revenue.

📄 Note:

  • If you're looking for a quick implementation guide, click here.
  • Find your ads.txt lines here

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Why is having an ads.txt important?

What is ads.txt? 

How does ads.txt work?

Can’t a spoofer just look at a site’s ads.txt file and use that information?

What are the reseller lines in the ads.txt file? 

How do I create an ads.txt file?

How do I properly format an ads.txt file? 

How can I tell if my ads.txt file is up to date?

How should I organize all my ads.txt lines in my ads.txt file?

Need an example?

Still need help?

Why is having an ads.txt important?

The International Advertising Bureau (IAB) implemented ads.txt in 2017 as a way to fight fraud by helping ad buyers avoid illegitimate sellers who arbitrage inventory and spoof domains. It’s important to publishers as well: ad buyers stopped purchasing inventory without ad updated ads.txt file at the end of 2019.

For more information on ads.txt, its importance, and its implementation, please visit the IAB guide to ads.txt. You can also visit our blog for valuable publisher news.

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.

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.


If you are a Publisher, and own and operate the content that goes on your website, you will need to use a "DIRECT" classification on your sovrn.com & lijit.com ads.txt lines.

Here's an example: 

lijit.com, 263669, DIRECT, fafdf38b16bf6b2b
lijit.com, 263669-eb, DIRECT, fafdf38b16bf6b2b

If you are an Intermediary, and you don't own and operate the content that goes on your website(s), you will need to use a "RESELLER" classification on your sovrn.com & lijit.com ads.txt lines.

Here's an example: 

lijit.com, 263669, RESELLER, fafdf38b16bf6b2b
lijit.com, 263669-eb, RESELLER, fafdf38b16bf6b2b


What are the reseller lines in the ads.txt file?

The reseller lines that appear in the ads.txt file create more supply paths to your inventory and cause more bids to occur. If Sovrn decides not to bid on an impression, we’ll send the requests to our resellers to see if they want to bid on the inventory.

These lines are not required, but they are beneficial. 

How do I create an ads.txt file?

Follow the steps below to create your ads.txt file. For WordPress users, you can easily download Ads.txt Manager. If you're not using WordPress, follow the instructions below.

1) Open or download a FTP service

  • File Transfer Protocol (FTP) is an easy way for you to transfer files from your computer to your website.
  • Sovrn recommends for WordPress users or FileZilla. It’s free, open source, and easy to use. 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.

  • Create a new .txt file and label it ads.txt.
    • To create a text or .txt file, all you need is a text editor or a word processing program such as Microsoft Word, WordPad, Notepad, or Atom.
    • Save the file in the .txt or Plain Text file format option. Make sure it’s in an easy-to-locate folder on your computer. We’ll add the required ads.txt information in steps 3 and 4.

3) Connect to your website using FTP

  • Open your FTP client and log in to your domain’s FTP using your web host credentials.
    • Web host credentials 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. For example, our new path is called  “domain.com/ads.txt”

6) Open your internet browser of your choice and ensure ads.txt is displaying correctly by visiting the new domain path you just created; “domain.com/ads.txt”.

How do I properly format an ads.txt file? 

📄 Note:Full IAB documentation can be found here.

Why is proper ads.txt formatting important?
Ads.txt errors can result in missed opportunities during the bidding process. DSPs use ads.txt as 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.

🚨Warning: Improper formatting will render the ads.txt file ‘unreadable’ and invalidate it, causing errors and lost revenue. 

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).
Required fields for each partner entry:
  1. Domain Name of the Advertiser: the operational domain of your exchange partner.
  2. Seller Account ID: the identification number associated with your account for this partner.
  3. Type of Relationship: the kind of relationship that your partners have with the selling of your inventory. The two options are:
    • 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.

Optional fields for each partner entry: 

  1. Certification Authority ID: an ID that uniquely identifies the advertising system within a certification authority.

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Format Checker

Want to check if your file properly formatted and ready to go? Check out AppNexus’ verification tool here.

Should I put ‘www.’ before each line? 

No! The domain in your entry should look like mywebsite.com and not www.mywebsite.com. Your ads.txt will be invalid if you use "www."

How can I tell if my ads.txt file is up to date? 

Make sure your file matches the one found in your account on the Platform here. 

How should I organize all my ads.txt lines in my ads.txt file? 

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.

  1. 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.
  2. Space out and label each grouping. Put a space between each partner grouping to make distinctions clearer. You might also label each group with the name of the associated partner to better track which grouping belongs to whom. Make sure to properly comment out your label of choice. This formatting requirement is a ‘#’ character.

Need an example?

The image below shows a great ads.txt page that you can use for inspiration. Please note that the example below is only meant to show how your ads.txt page could be organzied if you have many entries. You should not be use this in your site's ads.txt. Instead, find your specific ads.txt lines in your account here

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Still need help? 

If you’re struggling to implement or update your ads.txt file, don’t hesitate to reach out to publisher support and let us know that you need help with your ads.txt. We’ll be able to walk you through the steps to make sure you’re using ads.txt correctly.