• open source (BSD)
• in-memory data structure store that persists on disk
• used as a database, cache and message broker
• data model is key-value
• supports data structures such as strings, hashes, lists, sets, sorted sets with range queries, bitmaps, geospatial indexes with radius queries and streams
• has built-in replication, Lua scripting, LRU eviction, transactions and different levels of on-disk persistence
• provides high availability via Redis Sentinel and automatic partitioning with Redis Cluster

More-info:

• https://redis.io/
• https://en.wikipedia.org/wiki/Redis
• https://github.com/antirez/redis
• Redis for Windows
• Install Redis for local development