Build your own x

build-your-own-x

USE FOR:

• "build X from scratch / implement X yourself"
• "how does Docker/Git/database/web server actually work"
• "deep dive into how technology X is implemented"
• "learning compilers / interpreters / OS / networking internals"
• "implement neural network from scratch"
• "write your own shell / regex engine / search engine"
• "understand blockchain / BitTorrent internals" tags: [education, from-scratch, systems, compilers, OS, database, Docker, Git, neural-network, blockchain, web-server, shell, regex] kind: reference category: pro-code-architecture

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What Is Build-Your-Own-X?

Curated repo of step-by-step tutorials for recreating popular technologies from scratch.

"What I cannot create, I do not understand." — Richard Feynman

• Repo: https://github.com/codecrafters-io/build-your-own-x
• 300+ tutorials · 30 categories · 20+ programming languages
• Stars: 330,000+ (one of the most-starred repos on GitHub)

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Complete Category Reference

#	Category	What You Build	Languages
1	3D Renderer	Ray tracer, rasterizer, path tracer	C, C++, Java, JS, Python, Rust
2	AI Model	GPT, diffusion model, CLIP, NeRF	Python, C++
3	Augmented Reality	AR overlay, marker tracking	JS, Python
4	BitTorrent Client	Peer-to-peer file sharing	Go, Haskell, JS, Python, Rust
5	Blockchain / Crypto	Bitcoin-like chain, smart contracts	Go, Haskell, Java, JS, Python, Rust
6	Bot	Chatbot, IRC bot, Slack bot	Go, Java, JS, Python
7	Command-Line Tool	CLI parser, progress bar, formatter	Go, Python, Rust
8	Database	SQL engine, key-value store, Redis clone	C, C++, Go, Java, Python, Rust
9	Docker	Container runtime, image builder	Go, Python
10	Emulator / VM	CHIP-8, NES, Game Boy emulator	C, C++, Go, Java, JS, Rust
11	Frontend Framework	React-like library, virtual DOM, JSX	JS, TS
12	Game	Tetris, chess, Minecraft clone	C, C++, Go, Java, JS, Python
13	Git	Version control from scratch	Go, Python, Haskell, Ruby
14	Memory Allocator	malloc/free implementation	C
15	Network Stack	TCP/IP stack, HTTP client	C, Go, Python
16	Neural Network	Backprop from scratch, CNN, RNN	C, C++, Java, JS, Python
17	Operating System	Bootloader, kernel, process scheduler	C, Rust
18	Physics Engine	Rigid body, collision detection	C++, JS
19	Processor	RISC-V CPU in HDL or emulation	C, Python
20	Programming Language	Interpreter, compiler, VM, LISP	C, Go, Haskell, Java, JS, Python, Rust
21	Regex Engine	NFA/DFA regex from scratch	C, Go, Java, JS, Python
22	Search Engine	Inverted index, TF-IDF, BM25	Python, Ruby
23	Shell	Bash-like shell, job control	C, Go, Python, Rust
24	Template Engine	Jinja/Mustache-like	JS, Python
25	Text Editor	Vim-like, kilo editor	C
26	Visual Recognition	MNIST classifier, face detection	Python
27	Voxel Engine	Minecraft-style 3D world	C++
28	Web Browser	HTML parser, CSS layout, DOM	Python, Haskell
29	Web Server	HTTP/1.1, static file server	C, Go, Java, Python, Rust
30	Distributed Systems	Kafka-like, Raft consensus, MapReduce	Go, Java, Python

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Quick Lookup: "Build Your Own X" by Language

Python

• Neural network (numpy only), web server, shell, regex engine, search engine, blockchain, BitTorrent, Docker, browser, Git, database (Redis/SQLite clone)

Go

• Docker, Git, BitTorrent client, web server, shell, database, distributed systems (Raft/Kafka)

Rust

• OS kernel, web server, shell, regex engine, database, 3D renderer, BitTorrent

C / C++

• OS, memory allocator, text editor (kilo), 3D renderer, shell, neural network, database

JavaScript / TypeScript

• Frontend framework (React clone), game, bot, blockchain, web server, template engine

Java

• Blockchain, compiler, neural network, distributed systems

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Learning Path Recommendations

Systems Programming Track

1. Memory Allocator (C)          → understand heap
2. Shell (C/Go/Rust)             → processes, I/O, signals
3. Network Stack (C/Go)          → TCP/IP fundamentals
4. Web Server (Go/Rust)          → HTTP, concurrency
5. Operating System (C/Rust)     → kernel, scheduling

Compiler / Language Track

1. Regex Engine                  → NFA/DFA automata
2. Template Engine               → parsing basics
3. Interpreter (LISP/calc)       → AST, evaluation
4. Full Language (Python/Rust)   → lexer → parser → codegen

AI / ML Track

1. Neural Network (numpy/C)      → backprop from scratch
2. Visual Recognition (MNIST)    → CNN pipeline
3. AI Model (GPT-like)           → transformer architecture
4. Diffusion Model               → score-based generation

Distributed Systems Track

1. BitTorrent Client             → P2P, DHT
2. Blockchain                    → consensus, hashing
3. Kafka-like queue              → log-structured storage
4. Raft consensus                → leader election
5. MapReduce                     → distributed computation

Database Track

1. Key-value store (Redis clone) → in-memory, persistence
2. SQL engine                    → parsing, query planning
3. B-tree storage engine         → disk I/O, indexing
4. Full RDBMS                    → joins, transactions, ACID

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CodeCrafters Integration

Many guides are also available as interactive challenges at codecrafters.io:

• Build Redis, Git, Docker, HTTP server, SQLite, Kafka, BitTorrent
• Get automated test feedback as you build
• Supported languages: Go, Python, Rust, Java, C, C++, and more

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Using This as a Skill Reference

When a user asks "how does X work?" or "implement X from scratch":

1. Find X in the category table above
2. Route to the tutorial in preferred language
3. Use the learning path recommendations for sequencing
4. CodeCrafters for interactive guided versions

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