Buyers check ads.txt before they bid. If your file is wrong, the bid never happens — and nothing in your dashboard will tell you why revenue dropped.
1. The file is not at the root
It must be served from https://yourdomain.com/ads.txt, as plain text, with a 200 status. Not in a subfolder, not behind a redirect chain, not gated by Cloudflare bot protection.
2. Subdomains are forgotten
If you monetise m.yourdomain.com or blog.yourdomain.com, each host needs its own file or a valid subdomain referral line in the root file.
3. Stale reseller lines
Partners you left two years ago are still declared as authorised sellers of your inventory. That is a supply-path audit failure and some buyers will downweight you for it. Review the file quarterly.
4. DIRECT versus RESELLER is wrong
Declaring a reseller relationship as DIRECT is the single fastest way to get flagged in a supply-path optimisation audit. If you are not contracted directly with that seller, it is RESELLER.
5. The certification authority ID is missing
The fourth field — the TAG-ID — is optional in the spec and expected in practice. Include it for every partner that publishes one.
Our own lines are always current at /ads.txt. Copy them exactly, keep them in place, and re-check after any CDN or hosting migration.
Want us to run this check on your site?
Request a review