NodeElasticSearchExample. Elasticsearch is an open source search engine, which becomes hugely popular due to its high performance and distributed architecture. Elasticsearch is built on top of the Apache Lucene, which is a high-performance text search engine library. Although Elasticsearch can perform the storage and retrieval of data, its primary purpose is not to serve as a database. Instead, it is a search engine (server) with the primary goal of indexing, searching, and providing real-time statistics on the data.