Skip to content

Backgrounds

How-to Guides

Technical References

Set up the ads.txt file

The ads.txt specification is an IAB-approved text file to prevent unauthorized sales of inventory.  You can read more about it on their website: https://iabtechlab.com/ads-txt/

Setting It Up

Since requirements specify that the ads.txt file must be located in the root domain, we highly recommend placing the ads.txt file in your theme and then creating a rewrite rule for the URL. Here is an example:

// TODO: change `my_theme` prefix to my theme's prefix!
/**
 * Register the rewrite rule for /ads.txt request.
 */
function my_theme_adstxt_rewrite() {
    add_rewrite_rule( '^ads\.txt$', 'index.php?my_theme_adstxt=true', 'top' );
}
add_action( 'init', 'my_theme_adstxt_rewrite', 10 );
 
/**
 * Filter the list of public query vars in order to allow the WP::parse_request
 * to register the query variable.
 *
 * @param array $public_query_vars The array of public query variables.
 *
 * @return array
 */
function my_theme_adstxt_query_var( $public_query_vars ) {
    $public_query_vars[] = 'my_theme_adstxt';
    return $public_query_vars;
}
add_filter( 'query_vars', 'my_theme_adstxt_query_var', 10, 1 );
 
/**
 * Hook the parse_request action and serve the ads.txt when custom query variable is set to 'true'.
 *
 * @param WP $wp Current WordPress environment instance
 */
function my_theme_adstxt_request( $wp ) {
    if ( isset( $wp->query_vars['my_theme_adstxt'] ) && 'true' === $wp->query_vars['my_theme_adstxt'] ) {
        /*
         * Set proper content-type per specification in
         * https://iabtechlab.com/wp-content/uploads/2017/09/IABOpenRTB_Ads.txt_Public_Spec_V1-0-1.pdf :
         *
         * The HTTP Content-type should be ‘text/plain’, and all other Content-types should be treated
         * as an error and the content ignored.
         */
        header( 'Content-Type: text/plain' );
 
        // The code expects an existing ads.txt file in the root of your active theme.
        echo file_get_contents( get_stylesheet_directory() . '/ads.txt' );
        exit;
    }
}
add_action( 'parse_request', 'my_theme_adstxt_request', 10, 1 );

On WordPress.com, there should be no need to flush your rewrite rules, as it happens automatically upon deploy. For VIP Go, and in cases where the redirect does not work as expected, please head to VIP > Rewrite Rules and hit the “Flush Rewrite Rules” button.

Note

This is just one way to go about implementing ads.txt. Use the method that’s best suited to your theme.

If you’d like to be able to modify and validate your ads.txt file from the admin interface, the Ads.txt Manager plugin allows you to do so.

Last updated: April 09, 2021

Related Topics