Redis is an open-source, in-memory data structure store that is used as a database, cache, and message broker. It supports various data structures such as strings, hashes, lists, sets, sorted sets with range queries, bitmaps, hyperloglogs and geospatial indexes with radius queries. Redis provides high availability through master-slave replication where all writes go to the master node and are asynchronously replicated to one or more slave nodes. Redis also supports clustering for horizontal scaling. It was initially developed by Salvatore Sanfilippo in 2009 and has since become widely adopted for its performance, simplicity and versatility.
