Publish your ads.txt line

ads.txt is a plain text file on your website that lists who may sell your ad space. Your line in it proves the newsletter is yours, and MailAdx marketplace campaigns, deals and third-party DSPs depend on it.

Before you start

• Your website must be set on Account. The file lives at the root of that domain, such as yourdomain.com/ads.txt.
• You need to be able to add a file to your website, or ask someone who can.

Steps

1. Open Authorized Sellers.
2. Under Records to publish, select Copy the ads.txt line. The recommended OWNERDOMAIN line goes at the top of the file and names the business that owns the domain.
3. Add the line to your ads.txt file. Keep every line already in the file, because each one authorizes a different seller. Use plain text, with one record per line.
4. Keep the word DIRECT as it is.
5. Select Check now.

Where to put the file:

• WordPress: use an ads.txt plugin, or upload the file to the site's root folder, the one that holds wp-config.php.
• Static sites: add ads.txt to the folder your host serves from the root, often public/ or static/, and redeploy.
• Behind Cloudflare: a Cloudflare Worker can answer /ads.txt with your lines.
• Site builders: search your builder's help for "ads.txt". If it has no setting, a CDN in front of the site can serve the file.

What happens next

The page shows your status under Your ads.txt. MailAdx also checks every day at 03:30 UTC, and buyers' crawlers usually pick up a change within a day. You can run one check a minute.

What your inventory can earn shows what is open to you:

• Your own direct-sold campaigns always run.
• MailAdx marketplace campaigns and deals need your ads.txt line, or verification by the MailAdx team. Any deadline for existing publishers is shown on this page.
• Third-party DSPs (OpenRTB) need your ads.txt line and a listing in the seller list.

A brief failure to read your file doesn't remove your status straight away. MailAdx emails you if marketplace demand switches off or on.

The seller list (sellers.json)

sellers.json is the public list of sellers MailAdx works with. Buyers match your seller ID against it. MailAdx reviews your account for this list once your ads.txt shows Authorized.

Under Show my name in the seller list, choose one:

• Automatic — businesses shown, individuals kept confidential.
• Show my legal name and domain.
• Keep me confidential. Confidential sellers may get fewer bids.

Your name comes from the legal name in your billing details. An Owner, Admin or Manager can change this setting.

Newsletters on a shared domain

You can't place a file at the root of a shared domain such as substack.com, beehiiv.com, ghost.io, medium.com, kit.com or wordpress.com. Your direct-sold campaigns still run. For marketplace demand and deals, connect a custom domain you own to your newsletter, or write to support@mailadx.com and the team will verify your newsletter another way. Third-party DSPs check ads.txt themselves, so they need a domain you own.

If something goes wrong

• Line missing. The file exists but has no line for MailAdx. Add your line on its own line, and replace any placeholder.
• Wrong ID. Replace the line with the one on the page.
• RESELLER, not DIRECT. Change the word to DIRECT.
• File not found. Create a plain text file named ads.txt at the root of your domain.
• Web page, not a file. The address returned a web page, usually your "not found" page. Upload the file as plain text.
• Couldn't fetch. If your site is up, try again in a few minutes.
• Blocked address. Your domain points to a private or internal address. Check its DNS records.
• No domain. Add your website on Account.
• Shared platform. See the section above.
• "Checked less than a minute ago". Wait a minute and try again.
• The wrong domain is shown. Change your website on Account, then check again. A result from your old domain doesn't carry over.