Sphinx can be used in any web application that involves the searching of data. It can be a simple blog, shopping portal, or a very complex hotel or airline booking website. The most common use case of Sphinx is where searching needs to be fast and reliable.
The following is a list of scenarios where Sphinx will perform best:
Applications with a lot (billions of documents) of content
Applications that need to filter their search results based on numerous attributes (which are not full-text)
Applications where search is required on segregated data
Applications where data is coming from a non-conventional source such as a file system, mailboxes, NoSQL databases, and so on
Applications that need distributed searching so that load is balanced