Ask someone what a QA engineer does, and you'll probably hear a familiar answer: "They test software and find bugs." It's a common perception, and to be fair, finding bugs is an important part of the

A couple of months ago, I went for a 10K run with three different devices on me. Why? Another long story of review deadlines and my own procrastination. By the time I was done with my run and got back

We just published a brand new course on the freeCodeCamp.org YouTube channel that will take you from an absolute beginner to a Claude Code master. Whether you want to automate your development workflo

Imagine you're building an e-commerce platform where placing an order needs to trigger several things at once: the warehouse has to be told to prepare the shipment, the email service has to send a con

Most Flutter tutorials stop at network calls and REST APIs. The moment you need to talk to a physical device, a heart rate monitor, a smart bulb, a fitness tracker, an industrial sensor, or your own c

Imagine asking an AI assistant to de-identify thousands of medical images. It runs the pipeline, tracks progress, summarizes every decision, and tells you which files need human review, all without ev

There's a problem that shows up in almost every growing software system, and most developers don't even realize they're hitting it until the damage is already done. You have a set of objects: differen

In this tutorial, I’ll show you how to fine-tune a large language model for use in AI agents using supervised fine-tuning with QLoRA. This lets us customize a pre-trained model so it behaves the way w

For decades, recording an electrocardiogram (ECG) meant visiting a hospital or clinic. The doctors would place multiple electrodes on your chest and limbs to capture your heart's electrical activity.

I still remember the first time I ran a Bell-state circuit on a quantum simulator. The code was only a few lines long, but it felt magical. Two qubits became entangled, and the simulator returned almo

If you've ever built a web application or configured Spring Security, you've almost certainly encountered Cross-Site Request Forgery (CSRF). In my previous guide, How OAuth 2.0 Works: A Practical Guid

Reading PDF documents for long periods can become tiring, especially when the document contains bright backgrounds or when you're working in a low-light environment. In other situations, designers, de

When a workflow has more permissions than it needs, a simple build job can become a path to repository changes, token misuse, or a wider blast radius than the team intended. The problem is easy to mis

You've spent two weeks building an AI assistant. The streaming chat looks beautiful, the system prompt is tight, and safety filters are configured. You demoed it to the team, and everyone was impresse

Static sites are having a moment, and it makes sense. A folder of HTML, CSS, and JavaScript files is fast to load, cheap to host, and very hard to break. Tools like Astro, Eleventy, and Hugo build tha

Systems design has always been treated as a backend problem. Ask a group of Flutter engineers what systems design means, and most will describe server architecture: load balancers, databases, and micr

The gap between a demo that impresses and a system you can trust is measured in evals. I want to start with a story that's happening in hundreds of engineering teams right now. A team builds a RAG app

In 2022, I built a small micro-SaaS in my spare time and eventually sold it for a few thousand dollars. And today, with AI tools, it probably would've been even easier to build. But what has changed d

Your AI product shipped an agent-mode opt-in six months ago. You ran a propensity analysis, adjusted for engagement tier and query confidence, and reported a clean +8 percentage-point lift in task com

Picture this: it's 4pm on a Friday, and your team has just merged the last feature for the sprint. But your product manager asks for a new build on TestFlight by the end of the day so the client can r

Causal inference for LLM-based AI features is no longer theoretical. Airbnb, Netflix, Lyft, and Uber have published detailed engineering blog posts describing exactly how they measure the causal impac