Function and usage of domain_exists() in wordpress


Answers ( 1 )


    The domain_exists() function in WordPress is used to check whether a site name is already taken within a WordPress Multisite network. This function is particularly useful during the registration process of new sites in a network to ensure uniqueness of site names.

    Function Signature:

    domain_exists( string $domain, string $path, int $network_id = 1 ): int|null


    • The function checks for the existence of a site name within the WordPress network.
    • The site name could be a subdomain or a subdirectory path, depending on the network's configuration.
    • It is primarily used in the context of new site registration within a Multisite network.


    1. $domain (string, required): This parameter specifies the domain that needs to be checked. In the context of a WordPress network, this is typically the subdomain or the primary domain of the network.

    2. $path (string, required): This parameter indicates the path that needs to be checked. In a subdirectory installation, this would be the subdirectory path for the site.

    3. $network_id (int, optional): This is the ID of the network within which the check is to be performed. This parameter is only relevant in installations with multiple networks (a less common setup).

      • Default value: 1


    • int|null: The function returns the site ID if the site name (composed of the domain and path) exists within the specified network. If the site name does not exist, it returns null.

    Sample Usage:

    Here's an example of how domain_exists() might be used in a WordPress Multisite setup:

    // Check if a specific site name exists in the network
    $domain = 'example';
    $path = '/blog/';
    $network_id = 1; // Assuming single network setup
    $site_id = domain_exists($domain, $path, $network_id);
    if ($site_id) {
        echo "Site already exists with ID: " . $site_id;
    } else {
        echo "Site does not exist. Safe to register.";

    In this example, the function checks if a site with the subdomain 'example' and the path '/blog/' exists in the network with ID 1. It then outputs a message indicating whether the site exists or not.

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