Introduction

Why Redis?

Redis is the world's most popular in-memory data structure store. It is used as a cache, message broker, and database. Sub-millisecond response times, hundreds of thousands of operations per second.

  • Blazing fast — all data lives in RAM; reads and writes in microseconds
  • Versatile — strings, lists, sets, hashes, sorted sets, streams, and more
  • Persistent — optional disk persistence; data survives restarts
  • Atomic — single commands are atomic; no race conditions
  • Pub/Sub — built-in messaging between clients
  • TTL — keys expire automatically; perfect for sessions and caches

The Story

Redis was created by Salvatore Sanfilippo (antirez) in 2009 while working on a startup in Italy. He was frustrated with MySQL's performance for a real-time web analytics tool. He wrote the first version of Redis overnight and open-sourced it.

Redis stands for Remote Dictionary Server. Redis Labs (now Redis Inc.) funds its development. Redis 7.0 introduced radical improvements to performance and memory efficiency.

Who Uses Redis

Redis is used in production by virtually every major technology company:

  • Twitter — caches timelines and user data
  • GitHub — queues background jobs
  • Stack Overflow — caches question and answer data
  • Pinterest — stores social graphs
  • Snapchat — stores message metadata
  • Uber — geospatial real-time driver tracking

What You Will Learn

This course contains 15 lessons organized into 5 chapters:

  1. Strings — SET/GET, string operations, TTL/expiry, atomic counters.
  2. Collections — Lists, Sets, Hashes, and Sorted Sets.
  3. Key Operations — KEYS, TYPE, RENAME, and cursor-based SCAN.
  4. Patterns — Transactions, caching patterns, and leaderboards.
  5. Advanced — HyperLogLog and data modeling.

Each lesson explains a concept with examples and gives you an exercise to practice against a live Redis emulator in your browser.

Let's get started.

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