From scratch in Python

Build real systems in Python, and see exactly how they work: an operating system, a programming language, seven kinds of database, a network stack, a web server, Git, a search engine, a message queue, a job scheduler and a GPT-style language model.

A series of 18 projects that build real systems from scratch, to teach how they work. They are free, open source, and written for curious learners aged 12 and up.

Why build it yourself?

• Real, working systems. Each project runs. Boot PyOS and type commands into its shell, write a program in Pebble, query PyDB with SQL.
• Explained for learners. Every idea gets a plain-English page with an everyday analogy, written so a curious 12-year-old can follow. Grown-ups who never got to look inside are very welcome too.
• Nothing hidden in a library. The projects use only the Python standard library (PyLLM adds NumPy for fast arrays), so every interesting part is code you can read.
• Built test-first. Every feature was written with test-driven development, so the tests double as worked examples.

How to start

Start with PyOS or Pebble, then pick whatever interests you: each card says which earlier projects it builds on. PyStack at the end joins every project into one platform.

Every project is on PyPI as fromscratch-<name>. Install PyStack and you get the whole series:

pip install fromscratch-pystack

Start here

• PyOS

  Operating systems. Source

• Pebble

  Compilers and programming languages. Source

Storage

• PyDB

  Relational databases. Source

• PyKV

  Key-value stores. Source

• PyDocDB

  Document databases. Source

• PyGraphDB

  Graph databases. Source

• PyTSDB

  Time-series databases. Source

• PyVecDB

  Vector databases. Source

• PyColDB

  Column-family databases. Source

Systems

• PyCrypt

  Cryptography. Source

• PyNet

  Computer networking. Source

• PyWeb

  HTTP web servers. Builds on PyNet, PyCrypt. Source

• PyGit

  Version control. Source

• PySearch

  Search engines. Source

• PyMQ

  Message queues. Builds on PyNet. Source

• PyLLM

  Language models (the brain). Builds on Pebble. Source

• PyScheduler

  Job scheduling. Builds on PyDB, PyNet, PyWeb, PyMQ. Source

Putting it together

• PyStack

  Full-stack integration. Builds on PyOS, Pebble, PyDB, PyKV, PyDocDB, PyGraphDB, PyTSDB, PyVecDB, PyColDB, PyCrypt, PyNet, PyWeb, PyGit, PySearch, PyMQ, PyLLM, PyScheduler. Source

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Made by Rob Cox. Found a mistake or have an idea? Open an issue on any project's repository.