Build your own Redis in Node.js

Sibling to the Python and Go workshops. Same architectural progression, idiomatic Node.js: net.createServer, Buffer, Map, setInterval, async/await, event-driven everywhere.

The build

#	Step	New idea	LOC
01	TCP echo	net.createServer + data event	~30
02	RESP parser	Buffer + cursor + recursive parser	~110
03	GET / SET	Map + dispatch object, single-thread = no locks	~110
04	Expiry	Date.now() + setInterval for active sweep	~140
05	AOF persistence	fs.createWriteStream + readFileSync replay	~150
06	RDB snapshots	fs.writeFile + fs.rename, async BGSAVE	~130
07	Pub/Sub	Map<channel, Set>, conn.write fan-out	~140
08	Replication	SYNC + write streaming via net.connect	~150
09	Graceful shutdown	process.on(SIGTERM) + drain loop	~110
10	Capstone benchmark	Async worker pool, measure vs real Redis	~110

Each step folder ships with:

File	Purpose
server.mjs (or bench.mjs in step 10)	The runnable server
README.md	Run instructions and what's new
GUIDE.md	Deep-dive on the Node-specific idiom
EXERCISES.md	4 hands-on tasks

Getting started

Prerequisites

• Node.js 20+ (uses node: import scheme and parseArgs)
• Optional: redis-cli for talking to the server

Setup

git clone https://github.com/learnwithparam/build-your-own-redis-nodejs.git
cd build-your-own-redis-nodejs
make 01-tcp-echo

In another terminal:

nc localhost 6380
> hello
< hello

Run any step

make 01-tcp-echo
make 02-resp-parser
make 03-get-set
make 04-expiry
make 05-aof-persistence
make 06-rdb-snapshots
make 07-pubsub
make 08-replication
make 09-graceful-shutdown
make 10-capstone

Sibling courses

Same architecture in other languages:

• Build your own Redis in Python
• Build your own Redis in Go

Each language exposes different idioms for the same shape:

Concept	Python	Go	Node
Concurrency	Threads (step 7+) or selectors (step 9)	Goroutines from step 1	Event loop, single-thread
Shared state	dict + lock	map + sync.RWMutex	Map (no lock needed)
Background work	threading.Thread or asyncio	go func()	setInterval, async functions
BGSAVE	os.fork() with COW	Snapshot + goroutine save	async fs.writeFile
Graceful shutdown	signal.signal + flag	context.Context + WaitGroup	process.on(SIGTERM) + drain

Verifying your setup

make test

Runs an automated structural test suite.

License

MIT.