The WordPress search API plugin is the product of a Google Summer of Code project. It abstracts common methods and actions that would be useful in search engines and allows developers to write their own search engines for WordPress.

The main project also includes three example search plugins:

A MySQL plugin that uses FULLTEXT indexing for finding results in WordPress A Google plugin that uses Google Custom Search. A Sphinx plugin that uses the powerful sphinx backend search program.

In addition to allowing different types of search engines, the search plugin also allows extends the WordPress search capabilities to allow filtering by content type, advanced search by author, start date, end date, categories and more.