1. Sphinx is an open source full text search server, designed with performance, relevance (search quality), and integration simplicity in mind. Sphinx lets you either batch index and search data stored in files, an SQL database, NoSQL storage.

  2. Elasticsearch is an open source, distributed, RESTful search engine.

  3. Solr is an open source enterprise search server based on Lucene search library, with XML/HTTP and...

  4. Search Engines

  5. Xapian is an open source probabilistic information retrieval library, released under the GNU...