Apache Lucene Core

Apache Lucene™ is a high-performance, full-featured search engine library written entirely in Java. It is a technology suitable for nearly any application that requires structured search, full-text search, faceting, nearest-neighbor search across high-dimensionality vectors, spell correction or query suggestions.

Apache Lucene is an open source project available for free download. Please use the links on the right to access Lucene.

Lucene™ Features

Lucene offers powerful features through a simple API:

Scalable, High-Performance Indexing

  • over 800GB/hour on modern hardware
  • small RAM requirements -- only 1MB heap
  • incremental indexing as fast as batch indexing
  • index size roughly 20-30% the size of text indexed

Powerful, Accurate and Efficient Search Algorithms

  • ranked searching -- best results returned first
  • many powerful query types: phrase queries, wildcard queries, proximity queries, range queries and more
  • fielded searching (e.g. title, author, contents)
  • nearest-neighbor search for high-dimensionality vectors
  • sorting by any field
  • multiple-index searching with merged results
  • allows simultaneous update and searching
  • flexible faceting, highlighting, joins and result grouping
  • fast, memory-efficient and typo-tolerant suggesters
  • pluggable ranking models, including the Vector Space Model and Okapi BM25
  • configurable storage engine (codecs)

Cross-Platform Solution