Solr – Open Source Enterprise Search Platform
Solr is the popular, blazing-fast, open source enterprise search platform built on Apache Lucene. It is highly reliable, scalable and fault tolerant, providing distributed indexing, replication and load-balanced querying, automated failover and recovery, centralized configuration and more. Solr powers the search and navigation features of many of the world’s largest internet sites.
License: Apache 2.0 License