Redisearch implements a search engine on top of Redis, but unlike other redis search libraries, it does not use internal data structures like sorted sets.

Inverted indexes are stored as a special compressed data type that allows for fast indexing and search speed, and low memory footprint.

This also enables more advanced features, like exact phrase matching and numeric filtering for text queries, that are not possible or efficient with traditional Redis search approaches.

https://hub.docker.com/g/goodform/redisearch/

$ docker run -p 6379:6379 goodform/redisearch:latest

Got questions? Feel free to ask at the RediSearch mailing list.

• Full-Text indexing of multiple fields in documents.
• Incremental indexing without performance loss.
• Document ranking (provided manually by the user at index time).
• Field weights.
• Complex boolean queries with AND, OR, NOT operators between sub-queries.
• Prefix matching, fuzzy matching and exact phrase search in full-text queries.
• Auto-complete suggestions (with fuzzy prefix suggestions).
• Stemming based query expansion in many languages (using Snowball).
• Support for logographic (Chinese, etc.) tokenization and querying (using Friso)
• Limiting searches to specific document fields (up to 128 fields supported).
• Numeric filters and ranges.
• Geographical search utilizing Redis' own GEO commands.
• A powerfull aggregations engine.
• Supports any utf-8 encoded text.
• Retrieve full document content or just ids.
• Automatically index existing HASH keys as documents.
• Document deletion.
• Sortable properties (i.e. sorting users by age or name).

• Spelling correction

Which basically means you can freely use this for your own projects without "virality" to your code, as long as you're not modifying the module itself. See This Blog Post for more details.