REST API

From processes to web services

Author

Karsten Naert

Published

February 9, 2026

REST API — Section Overview

The title of this section is a bit of a misnomer—on purpose. We will get to REST APIs, but first we need to build up the machinery that makes them work. That means understanding processes, threads, interprocess communication, and networking fundamentals. Only then does the notion of a “client talking to a server over HTTP” really make sense.

Think of it as a journey from the bottom of the stack to the top.

Concurrency Foundations (Lectures 1–2)

We start by understanding how operating systems run multiple programs at once, and how Python can participate.

  • Lecture 1: Introduction to Processes and Threads — What processes and threads are, how to explore them with psutil, launch them with subprocess and multiprocessing, and coordinate them with synchronization primitives.
  • Lecture 2: Multiprocessing and Multithreading in Practice — Combining threads and processes in a real application: a TKinter GUI that spawns worker processes to approximate π with live visual feedback.

Communication and Networking (Lecture 3)

Once we have multiple processes, we need them to talk to each other.

Client-Server and the Web (Lectures 4–5)

With networking in hand, we zoom in on the dominant pattern of the modern web.


Ready? Start with Lecture 1: Introduction to Processes and Threads.