The Solr Redis Plugin is an extension for Solr that provides a query parser that uses data stored in Redis. It is open-sourced on Github by Sematext. This tool is basically a QParserPlugin that establishes a connection to Redis and takes data stored in SET, ZRANGE and other Redis data structures in order to build a query. Data fetched from Redis is used in RedisQParser and is responsible for building a query. Moreover, this plugin provides a highlighter extension which can be used to highlight parts of aliased Solr Redis queries (this will be described in a future).