Elasticsearch is a distributed RESTful search engine built for the cloud.
Features include:

  * Distributed and Highly Available Search Engine.
  * Multi Tenant with Multi Types.
  * Various set of APIs
  * Document oriented
  * Reliable, Asynchronous Write Behind for long term persistency.
  * (Near) Real Time Search.
  * Built on top of Lucene
  * Per operation consistency
  * Open Source under Apache 2 License.