Khaled Md Saifullah

Posted on Jan 31

Redis Explained: What It Is, Why Developers Use It and the Problems It Solves

#redis #backend #webdev

Introduction

If you have heard developers talk about Redis, you might wonder why it is such a big deal. Redis shows up in backend development, caching, real-time systems, session storage, queues and even gaming leaderboards.

This blog breaks down:

What Redis is
Why developers use Redis
What problems it solves
Real examples where Redis makes your app faster and better

Let’s dive in.....!

What Is Redis?

Redis is an open-source, in-memory data store often used as:

a cache
a database
a message broker

Redis stores data in RAM, not on disk, which makes it super fast often completing operations in under a millisecond.

Key Features

In-memory storage (Very Fast)
Supports many data types: strings, lists, sets, hashes, streams, sorted sets
Built-in replication and persistence options
Pub/Sub messaging
Widely used for caching and real-time apps

Why Do We Use Redis?

We use Redis mainly because it reduces load, improves speed and handles real-time data extremely well.

Redis makes your application much faster

Fetching data from a traditional database (like PostgreSQL or MongoDB) takes time. Redis stores data in memory → instant reads and writes.

Redis reduces database load

Instead of hitting your database over and over, you cache common data in Redis.

Redis helps build real-time features

Live chat
Notifications
Leaderboards
Real-time analytics

Redis powers background queues

Tools like BullMQ, Celery, Sidekiq and RQ all use Redis as a job manager.

What Problems Does Redis Solve?

Problem 1: Slow database queries

Redis Solution: Cache frequent data → faster responses

Problem 2: High traffic overload crashes databases

Redis Solution: Offload heavy reads → improve stability

Problem 3: Need for real-time communication

Redis Solution: Pub/Sub → instant messaging/notifications

Problem 4: Need for queues & background workers

Redis Solution: Redis lists/streams → simple and scalable job queues

Problem 5: Need to store short-term data (sessions, tokens)

Redis Solution: TTL support → auto-expiring keys

Real life Example: Using Redis as a Cache

Imagine your application shows a list of trending posts.

Without Redis

Every user request → hits database
Database becomes slow under heavy traffic
Higher costs on scaling the database

With Redis

You store trending posts in Redis:

const redis = require("redis");
const client = redis.createClient();

async function getTrendingPosts() {
  const cacheData = await client.get("trending_posts");

  if (cacheData) {
    return JSON.parse(cacheData);
  }

  const result = await fetchFromDatabase();

  await client.setEx("trending_posts", 300, JSON.stringify(result));

  return result;
}

Result

Faster response time
Lower database cost
Smooth performance even during high traffic

Where Is Redis Commonly Used?

Web apps (session store, caching)
Microservices (queues, shared state)
Gaming (leaderboards, matchmaking)
Real-time dashboards
Chat apps
E-commerce platforms (carts, inventory)
APIs handling huge traffic

Basically, if speed matters, Redis helps.

Summary

Redis is powerful because it solves performance and scaling problems that modern apps face. It is fast, flexible and works well with almost any technology stack.

In short

Redis is an in-memory data store
It makes apps significantly faster
It reduces stress on databases
Perfect for caching, real-time apps, queues and more

If you are building anything that needs speed, reliability, or real-time features, Redis is worth learning.

Final Thoughts

Redis is one of the most developer friendly tools available today. Whether you are building a small project or scaling a big one, Redis can dramatically improve performance.

DEV Community