Blazing fast search with Apache Solr
An open source search application that powers some of the most heavily used sites in the world.
Solr is highly reliable, scalable and fault tolerant. Powering the search and navigation features of many of the world's largest sites. Solr uses the Lucene Java search library at its core for full-text indexing and search, and has REST-like HTTP/XML and JSON APIs that make it easy to use from virtually any programming language. Solr's powerful external configuration allows it to be tailored to almost any type of application without Java coding, and it has an extensive plugin architecture when more advanced customisation is required.
Solr is a standalone enterprise search server with a REST-like API. Users put documents in it (called "indexing") via XML, JSON, CSV or binary over HTTP. and can run queries via HTTP GET to receive XML, JSON, CSV or binary results.