What ads.txt is
ads.txt (Authorized Digital Sellers) is a public text file, standardised by the IAB Tech Lab, that lists the companies allowed to sell ad space on your site. Buyers and exchanges read it before bidding. Sellers that are not on the list are treated as unauthorised, which blocks domain spoofing and keeps your ad revenue from going to someone pretending to be you.
Google AdSense and Ad Manager warn you in the dashboard when the file is missing or incomplete, and your earnings can drop until you fix it.
The format of each line
google.com, pub-1234567890123456, DIRECT, f08c47fec0942fa0
# Comments start with a hash sign
[email protected]A record has the ad system domain, your account ID in it, the relationship (DIRECT or RESELLER) and, optionally, the certification authority ID. Lines with contact=, subdomain=, OWNERDOMAIN= or MANAGERDOMAIN= are variables that add context. Blank lines and comments are ignored.
Where ads.txt must be served
Crawlers request https://your-domain/ads.txt at the root of the domain that shows the ads, and follow at most one redirect to another domain. The file must return HTTP 200 as plain text. Subdomains need their own file, or a subdomain= line in the root file of the main domain.
How we host ads.txt
Each company you add here has an ads.txt field. Paste your lines, save, and the file is served at https://your-app.freeprivacypolicy.app/ads.txt as text/plain, next to your privacy policy. We trim spaces and remove duplicate lines. You can show links to your ads.txt and app-ads.txt on your public company page, and update them from the dashboard, the REST API or your AI assistant.
If your ads run on your own domain, copy the same lines to /ads.txt there, or redirect that path to your file here: crawlers accept one redirect.
ads.txt, app-ads.txt and sellers.json
- ads.txt: published by websites, lists who may sell their ads.
- app-ads.txt: the same file for mobile and CTV apps, published on the developer website of the store listing.
- sellers.json: published by ad networks, lists the publishers they represent. Buyers match it against your ads.txt lines.