WordPress Multisite is a built-in feature of WordPress that allows multiple websites to be created and managed from a single WordPress installation, sharing one codebase and one database. Rather than installing WordPress separately for each site, a Multisite network lets a single administrator oversee many sites that all run on the same underlying files and infrastructure.
When Multisite is enabled, the WordPress installation becomes a network of sites, sometimes called a WordPress network or simply a network. Each individual site within that network has its own content, users, settings, and URL, but all sites draw from the same core WordPress files, themes, and plugins. This shared architecture significantly reduces the overhead of maintaining multiple independent installations, since updates to WordPress core, themes, and plugins can be applied once and propagated across the entire network.
The network is governed by a Super Admin, a special user role unique to Multisite that sits above the standard Administrator role. The Super Admin controls which themes and plugins are available across the network, manages individual sites, and can create or delete sites within the network. Each site can then have its own administrators who manage content and users within their own site, without access to the broader network settings.
WordPress Multisite supports two URL structures for individual sites: subdomain-based (for example, site1.example.com) and subdirectory-based (for example, example.com/site1). The choice between these structures is made during network setup and has implications for DNS configuration, SSL certificate management, and SEO, since search engines treat subdomains and subdirectories differently in terms of authority and indexing.
From a deployment perspective, Multisite simplifies the management of large portfolios of sites, making it a common choice for universities, media companies, agencies, and SaaS platforms that offer WordPress-powered sites to their users. However, the shared database and codebase also mean that a poorly coded plugin or a server-level issue can affect every site on the network simultaneously, so careful vetting of network-activated plugins is important.
It is worth noting that not all plugins are compatible with WordPress Multisite. Some plugins are designed only for standard single-site installations and may behave unpredictably in a network environment. When building or maintaining a Multisite network, verifying plugin compatibility is a necessary step in the development and deployment workflow.
WordPress Multisite is best suited to scenarios where multiple sites genuinely share a common purpose, design language, or administrative team. For sites that require highly divergent configurations or isolated environments, separate WordPress installations may remain the more practical choice.