Redis as cache vs data store vs message broker

Introduction

Redis can be used in different ways to make apps faster, store data, or help parts of an app talk to each other.

When you want to quickly save and get data to make your app faster (cache).

When you need a simple place to keep data that your app uses often (data store).

When different parts of your app need to send messages or alerts to each other (message broker).

Syntax

Redis

SET key value
GET key
PUBLISH channel message
SUBSCRIBE channel

SET and GET are used to save and get data in Redis.

PUBLISH and SUBSCRIBE are used for sending and receiving messages.

Examples

Save the name John under user:1 and get it back.

Redis

SET user:1 "John"
GET user:1

Send a message to the news channel and listen for messages on it.

Redis

PUBLISH news "Hello subscribers!"
SUBSCRIBE news

Sample Program

This example shows Redis used as a cache by counting page views, as a data store by saving the count, and as a message broker by sending and receiving alerts.

Redis

SET page:view:123 1
GET page:view:123
INCR page:view:123
GET page:view:123

PUBLISH alerts "New user signed up"

SUBSCRIBE alerts

Important Notes

As a cache, Redis stores data temporarily to speed up access.

As a data store, Redis keeps data that apps need to use often.

As a message broker, Redis helps parts of an app communicate by sending messages.

Summary

Redis can be used in three main ways: cache, data store, and message broker.

Cache makes apps faster by saving data temporarily.

Data store keeps data for apps to use.

Message broker helps parts of apps talk by sending messages.