Elasticsearch

Elasticsearch is the industry standard for full-text search, log analytics, and real-time data exploration. Built on Apache Lucene, it powers search features for Wikipedia, GitHub, Stack Overflow, and thousands of enterprises. The ELK Stack (Elasticsearch, Logstash, Kibana) is the dominant open-source observability platform. Beyond search, Elasticsearch handles geospatial queries, vector similarity search for AI, and time-series analytics. Its distributed architecture scales horizontally to handle petabytes of data.