Why Cache stores (memory, Redis) in NestJS? - Purpose & Use Cases

The Big Idea

What if your app could remember answers and skip slow steps every time?

The Scenario

Imagine your NestJS app fetching user data from a database every time someone visits a profile page.

Each request repeats the same slow database query, making users wait longer and servers work harder.

The Problem

Manually repeating database calls wastes time and resources.

It causes slow responses, higher server load, and poor user experience.

Trying to store data yourself without a proper cache system leads to messy code and bugs.

The Solution

Cache stores like memory or Redis save frequently used data temporarily.

They let your app quickly return data without hitting the database every time.

This makes your app faster, lighter, and more reliable.

Before vs After

✗ Before

const user = await database.findUser(id); // every request hits DB

✓ After

const user = await cache.get(id) || await database.findUser(id); await cache.set(id, user);

What It Enables

Cache stores enable lightning-fast responses and scalable apps by reducing repeated work.

Real Life Example

When you refresh a social media feed, cached posts load instantly instead of waiting for the server to fetch them again.

Key Takeaways

Manual repeated data fetching slows apps and wastes resources.

Cache stores save data temporarily for quick reuse.

Using memory or Redis caches makes NestJS apps faster and more efficient.