Query preprocessing for search engines
A flexible framework for rewriting and enriching search queries at the engine level — helping you tune relevance, manage synonyms, and control results without changing application code.
A powerful, extensible query rewriting pipeline
Querqy is an open source framework for query preprocessing in Java-based search engines. It lets you apply powerful rules to incoming queries — rewriting terms, expanding synonyms, boosting or filtering results, and replacing queries entirely — all managed externally without redeploying your application.
The built-in rewriters cover the most common relevance tuning needs: Common Rules for query-dependent rewrites, Word Break for handling compound words, and Replace for direct query substitution. You can also plug in your own rewriters to extend the pipeline.
Rules can be loaded from files, a database, or a rules management UI such as SMUI or Searchnik, making it straightforward for search teams to iterate on relevance without engineering involvement.
Tools built around the Querqy library
A web interface for managing Querqy rewriting rules, written with rules for Solr in mind. Supports query-dependent synonyms, filters, boosting and demotion, rule management per language, multiple deployment targets, and per-tenant rules.
A Docker Compose based reference implementation for e-commerce search using Solr and Elasticsearch. Brings together Querqy, SMUI, and complementary tools so you can get a working search platform up and running quickly.
Active search management, starting with Querqy rules on OpenSearch, Elasticsearch, and Solr. Adds a powerful UI and an API for versioning, review, and impact tracking to rule management, built by the team at OpenSource Connections.
Guides, articles, and talks
Need help with Querqy? The maintainers offer professional support — from setting Querqy up on your search engine to managing rules in production. Start with a free review call.
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