1. High-Level Data Structures
Provides five possible data types for values: strings, lists, sets, hashes, and sorted sets. Operations that are unique to those data types are provided and come with well documented time-complexity (Big O notation).
2. High Performance
Due to its in-memory nature, the project maintainer’s commitment to keeping complexity at a minimum, and an event-based programming model, Redis boasts exceptional performance for read and write operations.
3. Lightweight With No Dependencies
Written in ANSI C, and has no external dependencies. Works well in all POSIX environments. Windows is not officially supported, but an experimental build is provided by Microsoft.
4. High Availability
Built-in support for asynchronous, non-blocking, master/slave replication to ensure high availability of data. There is currently a high-availability solution called Redis Sentinel that is currently usable, but is still considered a work in progress.