Hi there, You’ve probably heard of the SOLID principles... and maybe even felt guilty for not applying them more. But how useful are they really when you’re writing Python? In my latest video, I take a simple but realistic example and implement it three ways: A messy, all-in-one class that gets the job done A cleaner, class-based version that follows SOLID principles A lightweight, functional approach that may be more Pythonic In the end, the important thing is to understand where design...
13 days ago • 1 min read
Hi there, You’ve probably heard it before: "Singletons are an anti-pattern!" And… yes. They often are. Especially when they’re used to add global state to your app and create coupling and bugs. But... there’s a different side of the Singleton pattern. In this week’s video, I cover why Singletons get a bad reputation. I'll also show you a practical use case where Singleton might actually be helpful. Enjoy the video, and hope you have a great weekend. Cheers, Arjan Do you enjoy my content on...
20 days ago • 1 min read
Hi there, You’ve probably noticed this by now: LLM prototypes are easy to build. But as soon as you try to turn them into actual production LLM systems… a lot more goes into it. In this week’s video, I walk through how to structure AI agents in Python using design patterns like Chain of Responsibility, Observer, and Strategy. I’ll build a fully functional travel assistant using Pydantic AI and explore how to make your agent pipelines more maintainable, testable, and modular. Hope you enjoy...
27 days ago • 1 min read
Hi there, I have to admit, I often forget how powerful the Python standard library is. Whenever I'm working on some project, I have to remind myself to consider whether something I need is already there, ready for me to use. So, in this week’s video, I’m looking at 10 of the most useful and underrated modules in Python’s standard library, including pathlib, heapq, graphlib, and more. These tools can help you write cleaner, faster, and more maintainable code without adding a single dependency....
about 1 month ago • 1 min read
Hi there, If you’ve been experimenting with trying to integrate AI into your code, you’ve probably run into the same problem I have: unstructured, unpredictable output. And the other way around: how do you let AI agents interact with your own code? That’s where Pydantic AI comes in. In this week's video, I show how to use Pydantic AI to embed an LLM agent directly into your Python app: with structured input, validated output, and access to real business logic. What I love about this approach...
about 1 month ago • 1 min read
Hey there, We all want to grow: as developers, as professionals, as people. But there’s one habit that can keep you from reaching your full potential. I’ve struggled with it my whole career, and I’ve seen countless other developers fall into the same trap: making assumptions and never questioning them. Early in my startup days, I dismissed React because I thought it wasn’t worth my time. I was wrong. More recently, I almost ignored AI coding tools for the same reason. These moments taught me...
about 2 months ago • 1 min read
Hey there, Writing software tests doesn't have to be hard. In my latest video, I walk you through how to write unit tests in Python with pytest Here’s what you’ll learn: The basics of unit testing (and why they matter) The difference between mocking and monkey patching, and when to use each How to refactor code for better testability How to use pytest fixtures to avoid repetition Advanced pytest features like parametrize, raises, skip, and xfail You’ll see multiple approaches in action, from...
about 2 months ago • 1 min read
Hey there, I've been using uv for all my Python projects lately. If you haven't made the switch yet from poetry, or pip/virtualenv/setuptools, this is a great time to try the tool. In my latest video, I walk through the latest updates to uv, including a hands-on demo of how uv now handles project setup, dependency management, syncing, and more, all from one tool. Uv now includes a fully integrated build backend, and as of version 0.8.0, it’s the default. That means no more extra config, and...
2 months ago • 1 min read
Hey there, As you've probably discovered Python’s ecosystem is massive. Knowing which libraries to use will help you get your work done much faster. A couple of weeks ago, I asked you in a YouTube community post which libraries you're using that more people should know about. So in this week's video, I go over 14 modern Python libraries you probably haven’t used yet, but absolutely should. I cover tools for: Functional programming Modern pagination in APIs Slick console output and TUIs...
2 months ago • 1 min read