What are Redis and Valkey?

Redis is the open source, in-memory key/value store behind countless caches, queues and leaderboards. Valkey started in 2024 as a fork of Redis under the Linux Foundation. They speak the same protocol, so everything in these tutorials works on both, and KVNest runs either.

What is an in-memory key/value store good for?

Anything that has to be fast: caching, sessions, counters, leaderboards, rate limits, queues and real-time messaging. The data lives in RAM, so most commands run in microseconds on the server.

Do I need an account?

No. Every level has a sandbox that runs in your browser. To run the programs against a real Redis or Valkey, sign up and create a free Starter instance; it takes about a minute.

The tutorials are free, and so is the Starter plan during the preview. The advanced track needs a persistent plan, Casual or Pro, which are coming soon.

Which languages are covered?

Node.js with iovalkey, Python with valkey-py, Go with go-redis and Java with Jedis. Each level has a complete program you can copy and run.

Does the code work with Redis too?

Yes. Every command in the beginner track exists in Redis 7 and newer, so the programs run against Redis as well.

KVNest

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Tutorials

Learn Redis and Valkey by building a game

Short levels, real code in your language, and a sandbox in your browser. Earn XP, unlock achievements, and find out what an in-memory key/value store can do.

Start the beginner track Choose a track

Valkey sandbox · runs in your browser

Type a command, or pick one below. Up and down arrows recall history.

sandbox>

Try

A real-ish Valkey, right here. No account needed.

Choose your track

Both tell one story, level by level, in Node.js, Python, Go or Java.

BeginnerFree on Starter9 levels · 45 min

Build a game backend

Caching, counters, a live leaderboard, rate limiting and pub/sub: the backend of a tiny arcade game, one level at a time.

1Insert coinConnect and PING
2Save the gameStrings and expiry (TTL)
3Turbo modeCaching with cache-aside
4Count everythingAtomic counters
5High scoresLeaderboards with sorted sets
6Player profilesHashes
7Anti-cheatRate limiting
8Live feedReal-time messaging with pub/sub
9Boss levelPut it all together

Start in

Node.js Python Go Java

AdvancedComing soonCasual or Pro

Build a durable job pipeline

Streams, consumer groups, retries, locks and idempotency: background jobs that survive crashes and restarts.

Append-only log
Many hands
Nothing gets lost
One at a time
Charge once
Later, please
Survive a restart
Boss level

Casual and Pro are coming soon

Jobs have to survive a restart, so this track needs a plan with persistent storage.

See what's inside

What you'll know how to build

Each level is one data structure and a couple of commands, and each one is a pattern real apps run on every request.

Caches
Answer from memory instead of a slow database or API, and let stale data expire by itself.
Leaderboards
Sorted sets keep millions of scores in order. Ranks and top 10s in microseconds.
Counters
Views, likes and stock levels that never lose an update, however many servers write.
Rate limits
Stop brute force and API abuse with two commands and a timer.
Live updates
Push events to every connected client the moment they happen, with pub/sub.
Sessions and tokens
Keys that delete themselves: logins, one-time codes and carts that time out.

Pick your language

The same game, with a complete, tested program for every level.

Redis and Valkey tutorial for Node.js

With iovalkey. Needs Node.js 18 or newer.

Redis and Valkey tutorial for Python

With valkey-py. Needs Python 3.9 or newer.

Redis and Valkey tutorial for Go

With go-redis. Needs Go 1.22 or newer.

Redis and Valkey tutorial for Java

With Jedis. Needs Java 21 or newer and Maven.