ads.txt Checker & Validator
Check that your ads.txt is reachable, correctly formatted and lists your Google AdSense publisher ID the right way.
What this ads.txt checker validates
ads.txt (“Authorized Digital Sellers”) is a public text file where you list the ad networks allowed to sell your ad space. Buyers check it before they bid, and Google AdSense uses it to confirm the publisher ID on your pages is really yours. A missing or broken file is one of the most common reasons for the “Earnings at risk” warning in AdSense.
- Reachability: the file returns HTTP 200, as plain text, without leaving your domain through redirects.
- Soft 404s: a web page returned in place of the file is reported, not treated as valid.
- Record format: every line has a valid ad-system domain, an account ID, DIRECT or RESELLER, and an optional certification ID.
- Google records: publisher IDs must be
pub-plus 16 digits, your own account must be DIRECT, and the certification ID for google.com isf08c47fec0942fa0. - Housekeeping: duplicate lines and a missing final newline are flagged as warnings.
How the health score works
Every check starts at 100. Each kind of error costs 30 points and each kind of warning 8, with the score kept between 0 and 100. A problem that repeats on several lines (say, ten duplicate records) counts once in the score, and every affected line is still listed. Errors are problems that can stop ads being sold (a missing file, your publisher ID absent or wrong); warnings are worth fixing but rarely block revenue on their own.
Reading the Google AdSense line
A correct AdSense record has four comma-separated parts:
google.com— the advertising system.pub-XXXXXXXXXXXXXXXX— your publisher ID from AdSense → Account → Settings.DIRECT— you control this account directly.f08c47fec0942fa0— Google’s certification authority ID.
Other networks you work with will have their own lines. Some partners legitimately add google.com, …, RESELLER lines for accounts they manage, so the checker only treats RESELLER as an error when it’s attached to the publisher ID you entered.
For a deeper explanation of the file, read ads.txt explained. Once ads.txt is in order, check the rest of your site with the AdSense approval audit.
Limits of this check
The checker reads the file over https from the domain you enter. It can’t see your AdSense account, so it can’t confirm which partner lines your setup needs, and it doesn’t validate subdomain ads.txt files or app-ads.txt. AdSense’s own Sites page remains the final word on what Google has crawled.
Frequently asked questions
What does an ads.txt checker do?
It downloads https://yourdomain/ads.txt the way ad crawlers do, then checks every line: the advertising system domain, your account ID, DIRECT or RESELLER, and the optional certification ID. It also flags files that are missing, served as an HTML page instead of text, or redirected to another domain.
What is the correct ads.txt line for Google AdSense?
google.com, pub-0000000000000000, DIRECT, f08c47fec0942fa0 — with your own 16-digit publisher ID in place of the zeros. AdSense shows the exact line for your account under Sites → ads.txt.
Where does the ads.txt file go?
In the root folder of your domain, so it opens at https://yourdomain.com/ads.txt. It must be a plain-text file named exactly ads.txt, publicly reachable without a login.
Why does my ads.txt show as an HTML page?
That's a soft 404: the file doesn't exist, so your CMS or server returns your homepage or an error page with status 200. Ad crawlers read that as having no valid ads.txt. Upload a real text file to the site root.
How long until AdSense sees my updated ads.txt?
Google re-crawls ads.txt on its own schedule, often within a day but sometimes longer. The 'Earnings at risk' message clears once AdSense has crawled the corrected file.
Do you store the domains I check?
No. The domain and publisher ID you enter are used only to run the check and are not saved or logged.