Sonic is a fast, lightweight, and schema-less search backend.  It
ingests search texts and identifier tuples that can then be queried
against in a microsecond's time.

Sonic can be used as a simple alternative to super-heavy and
full-featured search backends such as Elasticsearch in some use-cases.
It is capable of normalizing natural language search queries,
auto-completing a search query and providing the most relevant
results for a query.  Sonic is an identifier index, rather than a
document index; when queried, it returns IDs that can then be used
to refer to the matched documents in an external database.

A strong attention to performance and code cleanliness has been
given when designing Sonic.  It aims at being crash-free, super-fast
and puts minimum strain on server resources.

WWW: https://github.com/valeriansaliou/sonic