WordPress Multisite is a built-in feature that lets you run multiple WordPress websites from a single WordPress installation. All sites in the network share the same WordPress core files, the same plugin and theme directories, and the same database server. Each site, however, maintains its own content, settings, uploads, and user roles. Think of it as one WordPress installation serving many separate websites, all managed from a central dashboard.
How WordPress Multisite Is Structured
When you enable Multisite, WordPress creates additional database tables for each site in the network. The main site keeps the standard set of tables (like wp_posts and wp_options), while each additional site gets its own prefixed set (like wp_2_posts, wp_3_options, and so on). The core files, plugin files, and theme files remain shared. This means you only need to update WordPress core once, and it applies to every site in the network.
Subdomain vs Subdirectory Setup
Multisite supports two URL structures out of the box:
- Subdomain setup: Each site gets its own subdomain, for example
blog.example.com,shop.example.com,news.example.com. This requires wildcard DNS configuration on your server so that all subdomains point to the same installation. - Subdirectory setup: Each site lives under a path on the same domain, for example
example.com/blog/,example.com/shop/,example.com/news/. This is simpler to configure but is only available for new installations (existing sites that have been running for more than a month are limited to subdomains).
With additional plugins or custom code, you can also map completely separate domains to individual sites in the network. For example, mybrand.com could point to one site while otherbrand.com points to another, all running on the same Multisite installation.
The Super Admin Role
Multisite introduces a special role called Super Admin. A Super Admin has full control over the entire network, including the ability to create and delete sites, install and activate plugins network-wide, manage themes, and add or remove users across all sites. Regular site administrators in a Multisite network have reduced capabilities compared to a single-site admin. They cannot install plugins or themes on their own; they can only activate plugins and themes that the Super Admin has made available.
Network-Activated Plugins vs Per-Site Plugins
Plugins in a Multisite network can be managed in two ways. A Super Admin can "network activate" a plugin, which enables it across every site in the network simultaneously. Alternatively, the Super Admin can make a plugin available without network-activating it, allowing individual site admins to activate or deactivate it on their own site. Not all WordPress plugins support Multisite properly. Some plugins store data in ways that conflict with the shared database structure, or they assume they are running on a single-site installation. Always check plugin compatibility before deploying to a Multisite network.
Shared User Tables
All sites in a Multisite network share the same user table. This means a user registered on one site can be granted access to other sites without creating a new account. The user's login credentials work across the entire network. Roles, however, are assigned per site. A user might be an Editor on one site and a Subscriber on another. This shared user system simplifies management for organizations where people need access to multiple sites.
When Multisite Makes Sense
Multisite is a good fit in specific scenarios:
- Universities and schools: Each department, faculty, or student organization gets its own site, all managed centrally by the IT department.
- Corporate intranets: Different divisions or regional offices run separate sites but share branding, plugins, and user accounts.
- Franchise businesses: Each franchise location has its own site with local content, while the parent company controls the design and plugin stack.
- Development agencies: Agencies managing many small client sites can use Multisite to reduce maintenance overhead, updating WordPress core and plugins once instead of dozens of times.
- Multilingual sites: Some teams prefer running a separate site per language rather than using a translation plugin, using Multisite to keep them connected.
When Multisite Does NOT Make Sense
Multisite is not always the right choice. Avoid it in these situations:
- Unrelated sites: If the sites have nothing in common (different owners, different purposes, different plugin needs), separate installations are easier to manage.
- Different hosting requirements: If one site needs a high-performance server while another is a simple blog, bundling them together creates unnecessary constraints.
- Plugin incompatibility: If your key plugins do not support Multisite, you will run into issues that are hard to debug and fix.
- Individual client control: If clients need full admin access including plugin installation, Multisite's restricted admin role will frustrate them.
Performance Considerations
Multisite adds some overhead because every request must determine which site in the network is being accessed. The shared database can become a bottleneck if many sites receive heavy traffic simultaneously. Object caching (with Redis or Memcached) is strongly recommended for Multisite networks. Large networks with hundreds of sites should also consider database replication and load balancing. On the positive side, sharing plugins and themes across sites means less disk space and fewer files for the server to manage compared to running dozens of separate installations.
Migrating Away from Multisite
Moving a site out of a Multisite network into a standalone WordPress installation is possible but not straightforward. You need to export the site's content, recreate the database tables without the Multisite prefix, move the uploads to the correct directory structure, and reconfigure plugins and settings. Several migration plugins support this process, but manual database adjustments are often necessary. It is worth considering this migration difficulty before committing to Multisite, especially if there is a chance the sites might need to be separated later.
What InspectWP Checks
InspectWP can detect whether a WordPress site is part of a Multisite network by analyzing WordPress indicators, URL structures, and network-specific patterns in the site's HTML output and response headers.