Below we describe 2 of the key Search Engines we use at Successive Technologies.
ElasticSearch is an open source, RESTful search engine built on top of Apache Lucene and released under an Apache license. It is Java-based and can search and index document files in diverse formats. It provides a distributed, multitenant-capable full-text search engine with an HTTP web interface and schema-free JSON documents.
Elasticsearch is an extremely flexible and powerful real-time distributed full text search and analytics engine. It's easy to operate and high performance engine uses standard RESTful APIs and JSON. Currently, Elastic Search is used for data analysis, content search and queries in projects like Foursquare, Mozilla and GitHub.