Search really has 3 main levels. 1. Core ranked inverted index data store (Lucene) 2. API layer on top of Lucene with easier query, index, data importing, sha

Search really has 3 main levels. 1. Core ranked inverted index data store (Lucene) 2. API layer on top of Lucene with easier query, index, data importing, sharding, etc. (Solr/Elastic Search) 3. Fully hosted API / UI for easier GUI for developers and search relevance engineers (Algolia, Lucidworks Fusion). The new hotness in search is currently Rust-based tooling. Rust is a great application for search as it's very performance-sensitive and data-structure heavy, and once the indexes are built are fairly stable, leading to the 90th+ percentile latencies and throughput to be much better than Lucene-based libraries that are built on top of the JVM. For the low level core search engine like Lucene (inverted indexes, TF-IDF ranking, etc), there's Tantivy [1] For the middle tier (ES) there's Sonic [2] MeiliSearch [3] is a play for the hipster open-source Algolia. It's in Rust, is MIT licensed, supports self-hosting, has an out of the box web interface. [1] https://github.com/tantivy-search/tantivy https://github.com/tantivy-search/tantivy [2] https://github.com/valeriansaliou/sonic https://github.com/valeriansaliou/sonic [3] https://github.com/meilisearch/MeiliSearch https://github.com/meilisearch/MeiliSearch