Algolia - Algolia's Search API makes it easy to deliver a great search experience in your apps & websites. Algolia Search provides hosted full-text, numerical, faceted and geolocalized search.
ElasticSearch - Elasticsearch is an open source, distributed, RESTful search engine.
SearchTap.io - SearchTap is a search technology that can easily integrate with websites and mobile apps to provide an Amazon-like search experience without writing any code. It solves search problems for websites, businesses, mobile apps and enterprise software.
Xapian - Xapian is an open source probabilistic information retrieval library, released under the GNU...
elasticsearch-head - A web front end for an elastic search cluster
Manticore search - https://www.