WordPress Multi-Site
FacetWP can be installed and used on sub-sites in a WordPress multi-site network setup.
However, FacetWP will only filter content within each individual sub-site. It cannot filter or search across sub-sites, and there a no plans to support this in the future.
Multi-site installation, license keys and activation
FacetWP can be activated in each sub-site individually, or you can use Network Activation (recommended). Note that in both situations, update notifications only appear in: My Sites > Network Admin > Plugins.
Your license key needs to be activated in the FacetWP settings for each sub-site individually, also if the plugin is Network Activated. It is possible to add the license key once in wp-config.php or functions.php, but it still needs to be activated manually in the settings for each sub-site individually.
Note that each sub-site counts against your license’s site limit.
Register and maintain facets and listings in one place
If you are using FacetWP with WordPress multi-site, it can be a hassle to have to add or change your facets and Listing Builder listings for each site individually, especially if you have many sites in the multi-site network.
Fortunately, there are two hooks available (facetwp_facets and facetwp_templates) with which you can register facets and listing templates programmatically. This way you can create and maintain your facets and listings in one place, your functions.php, as long as your network sites are using the same theme.
An added benefit of this approach is that your facet- and listing settings can be placed under version control (with git for example), making it easy to revert to previous sets of facets/listings or previous facet/listing settings.