Solr vs Sphinx: What are the differences?

What is Solr? 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.

What is Sphinx? Open source full text search server, designed from the ground up with performance, relevance (aka search quality), and integration simplicity in mind. Sphinx lets you either batch index and search data stored in an SQL database, NoSQL storage, or just files quickly and easily — or index and search data on the fly, working with Sphinx pretty much as with a database server. A variety of text processing features enable fine-tuning Sphinx for your particular application requirements, and a number of relevance functions ensures you can tweak search quality as well.

Solr and Sphinx can be categorized as "Search Engines" tools.

Some of the features offered by Solr are:

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

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

• Output formats: HTML (including Windows HTML Help), LaTeX (for printable PDF versions), ePub, Texinfo, manual pages, plain text
• Extensive cross-references: semantic markup and automatic links for functions, classes, citations, glossary terms and similar pieces of information
• Hierarchical structure: easy definition of a document tree, with automatic links to siblings, parents and children

"Powerful" is the primary reason why developers consider Solr over the competitors, whereas "Fast" was stated as the key factor in picking Sphinx.

According to the StackShare community, Solr has a broader approval, being mentioned in 139 company stacks & 42 developers stacks; compared to Sphinx, which is listed in 38 company stacks and 13 developer stacks.