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Ads.txt: How to Create, Implement, and Update

The ad industry loses up to $44 billion to ad fraud every year—and those numbers are rising. While the complex supply and demand chain increases profits, it opens the doors for sharp practices like domain spoofing and intermediary parties that buy up inventory and sell it at a higher price.

With ad fraud-related revenue loss on the rise, the IAB Tech Lab came up with an initiative to improve transparency in programmatic advertising.

What Is Ads.txt?

Authorized Digital Seller (abbreviated as ads.txt) is a list of all partners authorized to sell and resell a publisher’s inventory. The list, which is saved as a text file, is uploaded to the root domain, making it harder for fraudsters to claim inventory that doesn’t belong to them.

Creating and implementing ads.txt does not require any technical skill. Not only is an ads.txt file easy to create, but it takes only a few minutes to upload the file onto your website. They can be easily updated and edited, given that you have proper access to the root domain.

How to Create an Ads.txt File

Creating an ads.txt file is a straightforward process. If you’re using WordPress, all you need to do is download the Ads.txt Manager. For those who are not using WordPress, follow the instructions below:

  1. Download a File Transfer Protocol (FTP) Service. FTPs make it easy to transfer files from your computer to your website. As long as your ads.txt page has a file path that results in domain/ads.txt, how you go about creating that file is completely up to you.
  2. Create a text file with your ads.txt information. To create a text file (.txt), you’ll need to use a word processing program such as Microsoft Word, Notepad, WordPad, or Atom. Save the file in Plain Text file format or .txt option.
  3. Connect to your website with an FTP. Using your web host credentials, log into your domain’s FTP. These credentials were sent to you via email when you signed up for your website.
  4. Locate, select, and drag your .txt file to your website’s home directory. This will create a path that has the same file name as your domain.
  5. Check that your ads.txt is displaying correctly. To do this, simply open your web browser and visit the new domain path that you just created.
Two women use phone with ads in the background
Photo By LeoPatrizi Via Getty Images

Proper Ads.txt Formatting Instructions

It is important to properly format your ads.txt before adding it to your text file. Improper formatting renders the .txt file “unreadable.” Full IAB Tech Lab documentation can be found here.

There are three fields that are required for each partner entry:

  • The Advertiser’s Domain Name
  • Seller Account ID
  • Type of Relationship

There are two options for the type of relationship: DIRECT and RESELLER. Direct indicates that the publisher has a direct relationship with the exchange or SSP, while Reseller indicates that the publisher has authorized this advertiser to resell inventory through another party, on their behalf.

Avoiding Crawling Issues

Proper formatting for ads.txt file can be tricky, so be sure to pay attention to the following:

  • Make sure the ads.txt file is always available, even when re-crawling.
  • Place the file in the root domain so bots can read it quickly.
  • Do not put “www.” before each line when formatting. This will leave your inventory vulnerable to advertising fraud.
  • Avoid uploading more than one ads.txt file. If you wish to create and upload a new file, you must first delete the old one from your database.

The Bottom Line

While ads.txt doesn’t completely eliminate all fraud-related issues in ad tech, it does a great job of increasing transparency in the industry.

Today, many advertisers choose to buy their impressions only from eligible impressions, meaning that the impression was sold by a partner that was approved by the publisher and included on the ads.txt file. To avoid revenue loss, make sure you stay updated with each demand partner’s latest ads.txt lines that must be added to your text file. That being said, it isn’t recommended to add lines that you’re unfamiliar with. Be sure to keep track of which partner provided you with which lines and don’t hesitate to ask your demand partners for clarifications if any are needed.