WordPress Multisite: Setup, Use Cases, and Management

What Is WordPress Multisite?

WordPress Multisite allows you to run multiple WordPress websites from a single WordPress installation and database. All sites share core WordPress files, but each site has its own tables, uploads folder, themes, and plugins. This is ideal for: a company with multiple country websites sharing the same codebase, a university with department-specific sites, an agency managing dozens of client sites, or an educational platform with per-student sites.

Enabling Multisite

To enable Multisite, add define('WP_ALLOW_MULTISITE', true) to wp-config.php, then go to Tools > Network Setup. Choose between subdomains (site1.example.com) or subdirectories (example.com/site1). Subdomain setup requires a wildcard DNS record (*.example.com) pointing to your server. WordPress will provide the exact code to add to wp-config.php and .htaccess to activate the network.

Network Administration

After enabling Multisite, a new Super Admin role appears with access to the Network Admin dashboard. From here, you can create new sites, manage all sites and users across the network, install plugins and themes for the entire network, and configure network-wide settings. Site-level administrators can only manage their specific site. Plugin and theme activation is a two-step process: network activation (by super admin) and site activation.

Domain Mapping for Custom Domains

Multisite supports multiple domains via domain mapping. Each subsite can have its own custom domain (e.g., client1.com, client2.com) instead of using the subdomain/subdirectory structure. Point each domain's DNS to your server. WordPress Multisite has built-in domain mapping support since WordPress 4.5 — configure the site's domain in the Network Admin > Sites > Edit Site > Site Address.

Shared vs Site-Specific Resources

In a Multisite network, plugins can be network-activated (forced on all sites) or site-activated (optional per site). Must-use plugins (in wp-content/mu-plugins) are automatically active on all sites and cannot be deactivated by site admins. Themes can be made available for site admins to choose, or forced on specific sites. The uploads directory is split per site: wp-content/uploads/sites/2/ for site ID 2.

When NOT to Use Multisite

Multisite adds complexity — updates affect all sites simultaneously, a plugin conflict can break all sites, and database migrations are more complex. Avoid Multisite if: your sites have very different configurations, your team is not comfortable with WordPress internals, or you only have 2-3 sites (separate installations are simpler). For client work, separate installations give clients true independence and simpler maintenance — I recommend Multisite only when shared management is a core requirement.