Introduction:

I started this journey of recreating technologies to learn more about them. Quick list of recreated tools: Redis, Git, HTTP server, React clone, Vector DB, etc. The common format I followed for each project is, I first noted down main features I wanted to recreate. My goal was not to create an exact replica. It was to learn the tech better. So I focused on building Proof of Concept using easier languages like python and javascript compared to c++ and rust.

Recreating Redis in Node.js

What I Built

A simplified version of Redis — an in-memory key-value store — using Node.js. It supports basic commands like SET, GET, DEL, EXPIRE, etc, mimicking the Redis CLI experience.

How I Built It

• I used TCP sockets with the net module in Node.js to handle raw client connections.
• Parsed custom commands in RESP (Redis Serialization Protocol) format.
• Maintained an in-memory object as the core data store.
• Implemented basic expiration logic using setTimeout.

Features I Added

• String operations:
  PING, SET, GET, DEL, EXPIRE, TTL, INCR, DECR, LPUSH, RPUSH, LRANGE, LPOP, RPOP
• TTL (time-to-live) expiration support
• Implemented persistence (in-memory, snapshot, append-only)
• A command parser that supports pipelining

What I Learned

• How TCP servers handle low-level communication
• Why Redis uses RESP instead of plain JSON
• How TTL works under the hood and the challenges with expiring keys
• Why Redis is single-threaded and how it avoids locks

Other Projects

• Recreating Git in Node.js

  • What I built: Basic CLI with init, add, commit, log, diff
  • How I built it: File system diffing, SHA1 hashing, .git directory
  • Features: Staging area, history, diffing
  • What I learned: DAGs, content-addressed storage, commit objects

• React.js Clone in Javascript

  • What I built: Reconciliation, React Hooks
  • How I built it: Fiber-like structure, custom hooks
  • Features: useState, useEffect, diffing, re-render
  • What I learned: Rendering models, reactivity, component lifecycles

• HTTP Server in Python

  • What I built: Barebones server supporting routes and headers
  • How I built it: Using built-in socket module in python
  • Features: Routing, request/response parsing, HTML and JSON response
  • What I learned: HTTP protocol internals, status codes, headers

• Mini Programming Language in Javascript

  • What I built: Tokenizer, parser, interpreter
  • How I built it: AST construction, recursive descent parsing
  • Features: Variables, math expressions
  • What I learned: Lexical analysis, parsing, control flow internals

• Vector Store (FAISS-lite) in Python

  • What I built: Simple vector indexer with cosine similarity
  • How I built it: Using NumPy module in python
  • Features: Insert, search, delete, metadata
  • What I learned: ANN (Approximate Nearest Neighbors), similarity math, indexing

• Minimal Backend Framework

  • What I built: FastAPI like Python Framework
  • How I built it: Routing system, middleware, response helpers. All this on top of waitress server
  • Features: Request/response lifecycle, plug-and-play middleware
  • What I learned: How a backend framework works behind the scenes

• UI Library

  • What I built: A lightweight tailwind css based ui components
  • How I built it: Using storybook, react and vite
  • Features: Button, Input, Text, and Layout (Box and Stack) components
  • What I learned: How design systems are built and documentated using Storybook

Reflections

Why Rebuilding Matters

• You gain intuition that no documentation or tutorial can offer.
• You start to appreciate trade-offs in real-world software (performance vs. simplicity, DX vs. complexity).
• It makes you fearless in diving into the source code of popular tools.
• Bonus: It’s fun. Seriously.

Closing Thoughts

• If you’re ever stuck in tutorial hell or feel like you’re not really learning — try building the tool yourself.
• It won’t be perfect. That’s the point.
• In the end, it’s not about replacing Redis or Git — it’s about replacing your limits with curiosity.