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

Source: Dev.to

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

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 (e.g., PostgreSQL or MongoDB) takes time. Redis stores data in memory → instant reads and writes.
• Redis reduces database load – instead of hitting your database repeatedly, you cache common data in Redis.
• Redis helps build real‑time features such as live chat, notifications, leaderboards, and 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?

Real Life Example: Using Redis as a Cache

Imagine your application shows a list of trending posts.

Without Redis

• Every user request hits the 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.