ElastiCache is a managed service that helps simplify the delivery and consumption of caching services in the AWS cloud. Caching is a very important tool in the arsenal of any cloud architect since the way modern applications operate can always be improved. When delivering applications from the cloud, it is imperative to deliver operational excellence, which means we should always be striving to consume only the amount of resources that is required to deliver our application services at the level defined by the Service Level Agreement (SLA).

In short, we want to deliver the maximum amount of performance for the minimum amount of cost. One way to optimize the performance of your application is to relieve the backend from constantly having to deliver the same result from the same request.

Think of a game on your device; thousands, possibly millions, of users are going to be requesting dynamic information such as who has the top score. Now, if we have thousands (or millions) of instances of the same request being sent to the backend database, that might become very expensive. Why not store the response in some kind of cache and deliver the response to all of those users without having to involve the database server at all? And if the leader changes and the scoreboard only shows the new leader and score in a few seconds or minutes, it will not affect the game at all.