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ads.txt variables: CONTACT, SUBDOMAIN, OWNERDOMAIN and MANAGERDOMAIN

By the ads-txt.in team · Published November 8, 2026

Besides the main records, an ads.txt file can contain variables written as NAME=value on their own lines. They are optional, but they give buyers useful extra information.

CONTACT

Gives a way to reach the site owner about the file. It can be an email address, a web page or a phone number.

CONTACT=adops@example.com

SUBDOMAIN

Ad systems read ads.txt from the root domain. If a subdomain has its own separate ads.txt file, the root file can point crawlers to it:

SUBDOMAIN=news.example.com

See our guide on ads.txt for subdomains.

OWNERDOMAIN

Added in ads.txt version 1.1, OWNERDOMAIN names the business domain of the company that owns the website. It helps buyers match your site with the business shown in ad systems’ sellers.json files, especially when you own several websites.

OWNERDOMAIN=examplemedia.com

MANAGERDOMAIN

Also from version 1.1, MANAGERDOMAIN names a company that manages the ad inventory for you, such as an ad management partner. You may add an optional two-letter country code after a comma if the manager only handles a specific country.

MANAGERDOMAIN=adpartner.com
MANAGERDOMAIN=adpartner.com,IN

Only add MANAGERDOMAIN if a partner really manages your ads.

INVENTORYPARTNERDOMAIN

Used mainly in connected TV and similar environments where content and ad space are shared between partners. It names a partner whose own ads.txt or app-ads.txt should be consulted. Ordinary websites rarely need it.

Rules for variables

  • Write one variable per line.
  • Variable names are case-insensitive, but uppercase is the convention.
  • Variables can appear anywhere in the file, though many publishers put them at the top for clarity.

Our generator adds CONTACT, OWNERDOMAIN and MANAGERDOMAIN when you fill in those fields, and our validator flags unknown variables.

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