freeCodeCamp

How to Test AI Features in Flutter [Full Handbook]

Atuoha Anthony |
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... read more

How to Harden GitHub Actions Permissions with Least Privilege by Default

ILYAS RUFAI |
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... read more

How to Build a Browser-Based PDF Color Inverter Tool Using JavaScript

Bhavin Sheth |
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... read more

CSRF from Scratch: Browser Mechanics, Attacks, and Spring Security Implementation [Full Handbook]

Ashutosh Krishna |
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... read more

Why 2D Trapped-Ion Quantum Computers Could Be Easier to Scale Than 1D Architectures

Casmir Onyekani |
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... read more

How an ECG on a Wrist Wearable Works and How It Compares to a Clinical Test

Reetain Raina |
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.... read more

How to Customize an LLM for AI Agents using SFT and QLoRA

Darsh Shah |
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... read more

A Deep Dive into Behavioral Patterns: The Visitor Design Pattern and its Clean Operations Across Complex Object Structures

Oluwaseyi Fatunmole |
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... read more

How to Build a Privacy-First Medical Image De-Identification Agent with Claude and MCP

Lakshmi Mahabaleshwara |
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... read more

Bluetooth Low Energy in Flutter: A Handbook for Devs

Nikheel Vishwas Savant |
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... read more