Lucene vs Solr: What are the differences?

Developers describe Lucene as "A high-performance, full-featured text search engine library written entirely in Java". Lucene Core, our flagship sub-project, provides Java-based indexing and search technology, as well as spellchecking, hit highlighting and advanced analysis/tokenization capabilities. On the other hand, Solr is detailed as "An open source enterprise search server based on Lucene search library, with XML/HTTP and JSON APIs, hit highlighting, faceted search, caching, replication etc". Solr is the popular, blazing fast open source enterprise search platform from the Apache Lucene project. Its major features include powerful full-text search, hit highlighting, faceted search, near real-time indexing, dynamic clustering, database integration, rich document (e.g., Word, PDF) handling, and geospatial search. Solr is highly reliable, scalable and fault tolerant, providing distributed indexing, replication and load-balanced querying, automated failover and recovery, centralized configuration and more. Solr powers the search and navigation features of many of the world's largest internet sites.

Lucene and Solr belong to "Search Engines" category of the tech stack.

Some of the features offered by Lucene are:

• over 150GB/hour on modern hardware
• small RAM requirements -- only 1MB heap
• incremental indexing as fast as batch indexing

On the other hand, Solr provides the following key features:

• Advanced Full-Text Search Capabilities
• Optimized for High Volume Web Traffic
• Standards Based Open Interfaces - XML, JSON and HTTP

According to the StackShare community, Solr has a broader approval, being mentioned in 140 company stacks & 42 developers stacks; compared to Lucene, which is listed in 33 company stacks and 9 developer stacks.