Amazon ElastiCache (Redis and Memcached)

Amazon ElastiCache is a fully managed in-memory data store and cache service. It supports two popular open-source engines — Redis and Memcached — and delivers sub-millisecond latency for real-time applications. ElastiCache sits between your application and your database, dramatically reducing read load and improving response times.

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Why Caching Matters

Databases are optimised for durability, not speed. Even a fast database query takes 1–10 milliseconds. For data that is read frequently but changes infrequently, an in-memory cache reduces latency to microseconds and lowers the load (and cost) on your primary database.

Metric	Without Cache	With ElastiCache
Read latency	1–10 ms	50–500 μs
Database load	High	Reduced by 80–90%
Cost at scale	Higher DB instance size	Smaller DB + cache nodes
Application complexity	Lower	Slightly higher (cache invalidation logic)

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Redis vs Memcached