When Should You Use a Cache With MongoDB?

Tue, 05 May 2026 15:23:30 +0000

From time to time, I’ll run a design review for an application being migrated from a relational database onto MongoDB, where the customer shares an architectural diagram showing a caching layer (typically Redis) sitting between the app server and MongoDB.

I like to keep the architecture as simple as possible—after all, each layer brings its own complexity and management costs—so I’ll ask why the caching layer is there. Of course, the answer is always that it’s there to speed up data access. This reveals a misunderstanding of both the reason why caching layers were created and what MongoDB provides.

Andrew Morgan on foojay.io - Friends of OpenJDK

When Should You Use a Cache With MongoDB?