VuFind® is most commonly used as a front-end for a local Solr index, but it can be used in other ways as well. See Third-Party Content for a list of supported providers.
The key to using VuFind® without Solr is the defaultModule setting in config.ini.
By default, this setting is set to “Search,” which means that when you initially access VuFind®'s URL, you are forwarded to the Home action of the Search controller, which defaults the user to Solr searching.
If you prefer to use a different service, such as EDS or Summon, you can simply change this setting to the name of the appropriate controller, which in most cases will correspond to the name of the service you wish to access.
By default, VuFind®'s search box template defaults to Solr search options when accessed from “generic” pages such as user account pages or the search history screen. Starting with VuFind® 6.1, the defaultSearchBackend setting in the [Site] section of config.ini can be used to control the default search box behavior. Set it to the name of the search backend you wish to use by default (e.g. EDS, Summon, etc.).