Redis & Memcached Basics

### Memcached

Memcached is a high-performance, distributed memory object caching system. - **Pros:** Extremely simple, multi-threaded, and highly efficient for simple key-value string storage. - **Cons:** Only supports strings, no persistence (data is lost on restart).

### Redis

Redis is an in-memory data structure store, often used as a database, cache, and message broker. - **Pros:** Supports rich data types (Lists, Sets, Hashes), offers persistence (can save to disk), built-in replication, and advanced features like Pub/Sub. - **Cons:** Single-threaded design (historically, though optimized heavily), slightly more complex than Memcached.

For modern applications, Redis is typically the preferred choice due to its extreme versatility.