What I cannot build. I do not understand ― Richard Feynman
This repository is a compilation of well-written, step-by-step guides for re-creating our favorite technologies from scratch.
What I cannot create, I do not understand — Richard Feynman.
It's a great way to learn.
- 3D Renderer
- Augmented Reality
- BitTorrent Client
- Blockchain / Cryptocurrency
- Bot
- Command-Line Tool
- Database
- Docker
- Emulator / Virtual Machine
- Front-end Framework / Library
- Game
- Git
- Network Stack
- Neural Network
- Operating System
- Physics Engine
- Programming Language
- Regex Engine
- Search Engine
- Shell
- Template Engine
- Text Editor
- Visual Recognition System
- Voxel Engine
- Web Browser
- Web Server
- Uncategorized
- C++: Introduction to Ray Tracing: a Simple Method for Creating 3D Images
- C++: How OpenGL works: software rendering in 500 lines of code
- C++: Raycasting engine of Wolfenstein 3D
- C++: Physically Based Rendering:From Theory To Implementation
- C++: Ray Tracing in One Weekend
- C++: Rasterization: a Practical Implementation
- C# / TypeScript / JavaScript: Learning how to write a 3D soft engine from scratch in C#, TypeScript or JavaScript
- Java / JavaScript: Build your own 3D renderer
- Java: How to create your own simple 3D render engine in pure Java
- JavaScript / Pseudocode: Computer Graphics from scratch
- Python: A 3D Modeller
- C#: How To: Augmented Reality App Tutorial for Beginners with Vuforia and Unity 3D [video]
- C#: How To Unity ARCore [video]
- C#: AR Portal Tutorial with Unity [video]
- C#: How to create a Dragon in Augmented Reality in Unity ARCore [video]
- C#: How to Augmented Reality AR Tutorial: ARKit Portal to the Upside Down [video]
- Python: Augmented Reality with Python and OpenCV
- C#: Building a BitTorrent client from scratch in C#
- Go: Building a BitTorrent client from the ground up in Go
- Nim: Writing a Bencode Parser
- Node.js: Write your own bittorrent client
- Python: A BitTorrent client in Python 3.5
- ATS: Functional Blockchain
- C#: Programming The Blockchain in C#
- Crystal: Write your own blockchain and PoW algorithm using Crystal
- Go: Building Blockchain in Go
- Go: Code your own blockchain in less than 200 lines of Go
- Java: Creating Your First Blockchain with Java
- JavaScript: A cryptocurrency implementation in less than 1500 lines of code
- JavaScript: Build your own Blockchain in JavaScript
- JavaScript: Learn & Build a JavaScript Blockchain
- JavaScript: Creating a blockchain with JavaScript
- JavaScript: How To Launch Your Own Production-Ready Cryptocurrency
- JavaScript: Writing a Blockchain in Node.js
- Kotlin: Let’s implement a cryptocurrency in Kotlin
- Python: Learn Blockchains by Building One
- Python: Build your own blockchain: a Python tutorial
- Python: A Practical Introduction to Blockchain with Python
- Python: Let’s Build the Tiniest Blockchain
- Ruby: Programming Blockchains Step-by-Step (Manuscripts Book Edition)
- Scala: How to build a simple actor-based blockchain
- TypeScript: Naivecoin: a tutorial for building a cryptocurrency
- TypeScript: NaivecoinStake: a tutorial for building a cryptocurrency with the Proof of Stake consensus
- Rust: Building A Blockchain in Rust & Substrate
- Haskell: Roll your own IRC bot
- Node.js: Creating a Simple Facebook Messenger AI Bot with API.ai in Node.js
- Node.js: How to make a responsive telegram bot
- Node.js: Create a Discord bot
- Node.js: gifbot - Building a GitHub App
- Node.js: Building A Simple AI Chatbot With Web Speech API And Node.js
- Python: How to Build Your First Slack Bot with Python
- Python: How to build a Slack Bot with Python using Slack Events API & Django under 20 minute
- Python: Build a Reddit Bot
- Python: How To Make A Reddit Bot [video]
- Python: How To Create a Telegram Bot Using Python
- Python: Create a Twitter Bot in Python Using Tweepy
- Python: Creating Reddit Bot with Python & PRAW [video]
- R: Build A Cryptocurrency Trading Bot with R
- Rust: A bot for Starcraft in Rust, C or any other language
- Go: Visualize your local git contributions with Go
- Go: Build a command line app with Go: lolcat
- Go: Building a cli command with Go: cowsay
- Go: Go CLI tutorial: fortune clone
- Nim: Writing a stow alternative to manage dotfiles
- Node.js: Create a CLI tool in Javascript
- Rust: Command line apps in Rust
- Rust: Writing a Command Line Tool in Rust
- Zig: Build Your Own CLI App in Zig from Scratch
- C: Let's Build a Simple Database
- C++: Build Your Own Redis from Scratch
- C#: Build Your Own Database
- Clojure: An Archaeology-Inspired Database
- Crystal: Why you should build your own NoSQL Database
- Go: Build Your Own Database from Scratch: Persistence, Indexing, Concurrency
- Go: Build Your Own Redis from Scratch
- JavaScript: Dagoba: an in-memory graph database
- Python: DBDB: Dog Bed Database
- Python: Write your own miniature Redis with Python
- Ruby: Build your own fast, persistent KV store in Ruby
- Rust: Build your own Redis client and server
- C: Linux containers in 500 lines of code
- Go: Build Your Own Container Using Less than 100 Lines of Go
- Go: Building a container from scratch in Go [video]
- Python: A workshop on Linux containers: Rebuild Docker from Scratch
- Python: A proof-of-concept imitation of Docker, written in 100% Python
- Shell: Docker implemented in around 100 lines of bash
- C: Home-grown bytecode interpreters
- C: Virtual machine in C
- C: Write your Own Virtual Machine
- C: Writing a Game Boy emulator, Cinoop
- C++: How to write an emulator (CHIP-8 interpreter)
- C++: Emulation tutorial (CHIP-8 interpreter)
- C++: Emulation tutorial (GameBoy emulator)
- C++: Emulation tutorial (Master System emulator)
- C++: NES Emulator From Scratch [video]
- Common Lisp: CHIP-8 in Common Lisp
- JavaScript: GameBoy Emulation in JavaScript
- Python: Emulation Basics: Write your own Chip 8 Emulator/Interpreter
- Rust: 0dmg: Learning Rust by building a partial Game Boy emulator
- JavaScript: WTF is JSX (Let's Build a JSX Renderer)
- JavaScript: A DIY guide to build your own React
- JavaScript: Building React From Scratch [video]
- JavaScript: Gooact: React in 160 lines of JavaScript
- JavaScript: Learn how React Reconciler package works by building your own lightweight React DOM
- JavaScript: Build Yourself a Redux
- JavaScript: Let’s Write Redux!
- JavaScript: Redux: Implementing Store from Scratch [video]
- JavaScript: Build Your own Simplified AngularJS in 200 Lines of JavaScript
- JavaScript: Make Your Own AngularJS
- JavaScript: How to write your own Virtual DOM
- JavaScript: Building a frontend framework, from scratch, with components (templating, state, VDOM)
- JavaScript: Build your own React
- JavaScript: Building a Custom React Renderer [video]
- C: Handmade Hero
- C: How to Program an NES game in C
- C: Chess Engine In C [video]
- C: Let's Make: Dangerous Dave [video]
- C: Learn Video Game Programming in C [video]
- C: Coding A Sudoku Solver in C [video]
- C: Coding a Rogue/Nethack RPG in C [video]
- C: On Tetris and Reimplementation
- C++: Breakout
- C++: Beginning Game Programming v2.0
- C++: Tetris tutorial in C++ platform independent focused in game logic for beginners
- C++: Remaking Cavestory in C++ [video]
- C++: Reconstructing Cave Story [video]
- C++: Space Invaders from Scratch
- C#: Learn C# by Building a Simple RPG
- C#: Creating a Roguelike Game in C#
- C#: Build a C#/WPF RPG
- Go: Games With Go [video]
- Java: Code a 2D Game Engine using Java - Full Course for Beginners [video]
- Java: 3D Game Development with LWJGL 3
- JavaScript: 2D breakout game using Phaser
- JavaScript: How to Make Flappy Bird in HTML5 With Phaser
- JavaScript: Developing Games with React, Redux, and SVG
- JavaScript: Build your own 8-Ball Pool game from scratch [video]
- JavaScript: How to Make Your First Roguelike
- JavaScript: Think like a programmer: How to build Snake using only JavaScript, HTML & CSS
- Lua: BYTEPATH
- Python: Developing Games With PyGame
- Python: Making Games with Python & Pygame [pdf]
- Python: Roguelike Tutorial Revised
- Ruby: Developing Games With Ruby
- Ruby: Ruby Snake
- Rust: Adventures in Rust: A Basic 2D Game
- Rust: Roguelike Tutorial in Rust + tcod
- Haskell: Reimplementing “git clone” in Haskell from the bottom up
- JavaScript: Gitlet
- JavaScript: Build GIT - Learn GIT
- Python: Just enough of a Git client to create a repo, commit, and push itself to GitHub
- Python: Write yourself a Git!
- Python: ugit: Learn Git Internals by Building Git Yourself
- Ruby: Rebuilding Git in Ruby
- C: Beej's Guide to Network Programming
- C: Let's code a TCP/IP stack
- C / Python: Build your own VPN/Virtual Switch
- Ruby: How to build a network stack in Ruby
- C#: Neural Network OCR
- F#: Building Neural Networks in F#
- Go: Build a multilayer perceptron with Golang
- Go: How to build a simple artificial neural network with Go
- Go: Building a Neural Net from Scratch in Go
- JavaScript / Java: Neural Networks - The Nature of Code [video]
- JavaScript: Neural networks from scratch for JavaScript linguists (Part1 — The Perceptron)
- Python: A Neural Network in 11 lines of Python
- Python: Implement a Neural Network from Scratch
- Python: Optical Character Recognition (OCR)
- Python: Traffic signs classification with a convolutional network
- Python: Generate Music using LSTM Neural Network in Keras
- Python: An Introduction to Convolutional Neural Networks
- Python: Neural Networks: Zero to Hero
- Assembly: Writing a Tiny x86 Bootloader
- Assembly: Baking Pi – Operating Systems Development
- C: Building a software and hardware stack for a simple computer from scratch [video]
- C: Operating Systems: From 0 to 1
- C: The little book about OS development
- C: Roll your own toy UNIX-clone OS
- C: Kernel 101 – Let’s write a Kernel
- C: Kernel 201 – Let’s write a Kernel with keyboard and screen support
- C: Build a minimal multi-tasking kernel for ARM from scratch
- C: How to create an OS from scratch
- C: Malloc tutorial
- C: Hack the virtual memory
- C: Learning operating system development using Linux kernel and Raspberry Pi
- C: Operating systems development for Dummies
- C++: Write your own Operating System [video]
- C++: Writing a Bootloader
- Rust: Writing an OS in Rust
- Rust: Add RISC-V Rust Operating System Tutorial
- (any): Linux from scratch
- C: Video Game Physics Tutorial
- C++: Game physics series by Allen Chou
- C++: How to Create a Custom Physics Engine
- C++: 3D Physics Engine Tutorial [video]
- JavaScript: How Physics Engines Work
- JavaScript: Broad Phase Collision Detection Using Spatial Partitioning
- JavaScript: Build a simple 2D physics engine for JavaScript games
- (any): mal - Make a Lisp
- Assembly: Jonesforth
- C: Baby's First Garbage Collector
- C: Build Your Own Lisp: Learn C and build your own programming language in 1000 lines of code
- C: Writing a Simple Garbage Collector in C
- C: C interpreter that interprets itself.
- C: A C & x86 version of the "Let's Build a Compiler" by Jack Crenshaw
- C: A journey explaining how to build a compiler from scratch
- C++: Writing Your Own Toy Compiler Using Flex
- C++: How to Create a Compiler [video]
- C++: Kaleidoscope: Implementing a Language with LLVM
- F#: Understanding Parser Combinators
- Elixir: Demystifying compilers by writing your own [video]
- Go: The Super Tiny Compiler
- Go: Lexical Scanning in Go [video]
- Haskell: Let's Build a Compiler
- Haskell: Write You a Haskell
- Haskell: Write Yourself a Scheme in 48 Hours
- Haskell: Write You A Scheme
- Java: Crafting interpreters: A handbook for making programming languages
- Java: Creating JVM Language
- JavaScript: The Super Tiny Compiler
- JavaScript: The Super Tiny Interpreter
- JavaScript: Little Lisp interpreter
- JavaScript: How to implement a programming language in JavaScript
- JavaScript: Let’s go write a Lisp
- OCaml: Writing a C Compiler
- OCaml: Writing a Lisp, the series
- Pascal: Let's Build a Compiler
- Python: A Python Interpreter Written in Python
- Python: lisp.py: Make your own Lisp interpreter
- Python: How to Write a Lisp Interpreter in Python
- Python: Let’s Build A Simple Interpreter
- Python: Make Your Own Simple Interpreted Programming Language [video]
- Python: From Source Code To Machine Code: Build Your Own Compiler From Scratch
- Racket: Beautiful Racket: How to make your own programming languages with Racket
- Ruby: A Compiler From Scratch
- Ruby: Markdown compiler from scratch in Ruby
- Rust: Learning Parser Combinators With Rust
- Swift: Building a LISP from scratch with Swift
- TypeScript: Build your own WebAssembly Compiler
- C: A Regular Expression Matcher
- C: Regular Expression Matching Can Be Simple And Fast
- Go: How to build a regex engine from scratch
- JavaScript: Build a Regex Engine in Less than 40 Lines of Code
- JavaScript: How to implement regular expressions in functional javascript using derivatives
- JavaScript: Implementing a Regular Expression Engine
- Perl: How Regexes Work
- Python: Build Your Own Regular Expression Engines: Backtracking, NFA, DFA
- Scala: No Magic: Regular Expressions
- CSS: A search engine in CSS
- Python: Building a search engine using Redis and redis-py
- Python: Building a Vector Space Indexing Engine in Python
- Python: Building A Python-Based Search Engine [video]
- Python: Making text search learn from feedback
- Python: Finding Important Words in Text Using TF-IDF
- C: Tutorial - Write a Shell in C
- C: Let's build a shell!
- C: Writing a UNIX Shell
- C: Build Your Own Shell
- C: Write a shell in C
- Go: Writing a simple shell in Go
- Rust: Build Your Own Shell using Rust
- JavaScript: JavaScript template engine in just 20 lines
- JavaScript: Understanding JavaScript Micro-Templating
- Python: Approach: Building a toy template engine in Python
- Python: A Template Engine
- Ruby: How to write a template engine in less than 30 lines of code
- C: Build Your Own Text Editor
- C++: Designing a Simple Text Editor
- Python: Python Tutorial: Make Your Own Text Editor [video]
- Python: Create a Simple Python Text Editor!
- Ruby: Build a Collaborative Text Editor Using Rails
- Rust: Hecto: Build your own text editor in Rust
- Python: Developing a License Plate Recognition System with Machine Learning in Python
- Python: Building a Facial Recognition Pipeline with Deep Learning in Tensorflow
- C#: Writing a Web Server from Scratch
- Node.js: Build Your Own Web Server From Scratch In JavaScript
- Node.js: Let's code a web server from scratch with NodeJS Streams
- Node.js: lets-build-express
- PHP: Writing a webserver in pure PHP
- Python: A Simple Web Server
- Python: Let’s Build A Web Server.
- Python: Web application from scratch
- Python: Building a basic HTTP Server from scratch in Python
- Python: Implementing a RESTful Web API with Python & Flask
- Ruby: Building a simple websockets server from scratch in Ruby
- (any): From NAND to Tetris: Building a Modern Computer From First Principles
- (any): build-your-own-x-vibe-coding: BYOX-style tutorials adapted for vibe coding
- Alloy: The Same-Origin Policy
- C: How to Write a Video Player in Less Than 1000 Lines
- C: Learn how to write a hash table in C
- C: The very basics of a terminal emulator
- C: Write a System Call
- C: Sol - An MQTT broker from scratch
- C++: Build your own VR headset for $200
- C++: How X Window Managers work and how to write one
- C++: Writing a Linux Debugger
- C++: How a 64k intro is made
- C++: Make your own Game Engine
- C#: C# Networking: Create a TCP chater server, TCP games, UDP Pong and more
- C#: Loading and rendering 3D skeletal animations from scratch in C# and GLSL
- Clojure: Building a spell-checker
- Go: Build A Simple Terminal Emulator In 100 Lines of Golang
- Go: Let's Create a Simple Load Balancer
- Go: Video Encoding from Scratch
- Java: How to Build an Android Reddit App [video]
- JavaScript: Build Your Own Module Bundler - Minipack
- JavaScript: Learn JavaScript Promises by Building a Promise from Scratch
- JavaScript: Implementing promises from scratch (TDD way)
- JavaScript: Implement your own — call(), apply() and bind() method in JavaScript
- JavaScript: JavaScript Algorithms and Data Structures
- JavaScript: Build a ride hailing app with React Native
- JavaScript: Build Your Own AdBlocker in (Literally) 10 Minutes
- Kotlin: Build Your Own Cache
- Lua: Building a CDN from Scratch to Learn about CDN
- Nim: Writing a Redis Protocol Parser
- Nim: Writing a Build system
- Nim: Writing a MiniTest Framework
- Nim: Writing a DMIDecode Parser
- Nim: Writing a INI Parser
- Nim: Writing a Link Checker
- Nim: Writing a URL Shortening Service
- Node.js: Build a static site generator in 40 lines with Node.js
- Node.js: Building A Simple Single Sign On(SSO) Server And Solution From Scratch In Node.js.
- Node.js: How to create a real-world Node CLI app with Node
- Node.js: Build a DNS Server in Node.js
- PHP: Write your own MVC from scratch in PHP
- PHP: Make your own blog
- PHP: Modern PHP Without a Framework
- PHP: Code a Web Search Engine in PHP
- Python: Build a Deep Learning Library [video]
- Python: How to Build a Kick-Ass Mobile Document Scanner in Just 5 Minutes
- Python: Continuous Integration System
- Python: Recommender Systems in Python: Beginner Tutorial
- Python: Write SMS-spam detector with Scikit-learn
- Python: A Simple Content-Based Recommendation Engine in Python
- Python: Stock Market Predictions with LSTM in Python
- Python: Building a simple Generative Adversarial Network (GAN) using Tensorflow
- Python: Learn ML Algorithms by coding: Decision Trees
- Python: JSON Decoding Algorithm
- Python: Build your own Git plugin with python
- Ruby: A Pedometer in the Real World
- Ruby: Creating a Linux Desktop application with Ruby
- Rust: Building a DNS server in Rust
- Rust: Writing Scalable Chat Service from Scratch
- Rust: WebGL + Rust: Basic Water Tutorial
- TypeScript: Tiny Package Manager: Learns how npm or Yarn works
- Submissions welcome, just send a PR.
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