How many times have you rewritten the same systems across different Unity projects? Or copied entire folders from an old project, only to spend hours fixing references, renaming namespaces, and adapti

I was recently moved to the marketing team at my company, and that shift has made me reflect more deeply on the role documentation plays in our go-to-market strategy. Before this move, we've had sever

Java is the most widely used programming language for enterprise software, Android development, and university computer science courses. Apple doesn't include Java with macOS, so you need to install i

If you've ever wanted to combine the power of Rust with the interactive goodness of Jupyter notebooks, you're in the right place. Maybe you're tired of compiling every single time you want to test a s

WhatsApp bots are widely used for customer support, automated replies, notifications, and internal tools. Instead of relying on expensive third-party platforms, you can build and deploy your own self-

Today Quincy Larson interviews Shawn Wang. He's a software engineer, founder of the AI Engineer conference, and host of the Latent Space podcast focused on applying the latest models toward getting wo

AI agents are all the rage these days. They’re like traditional chatbots, but they have the ability to utilize a plethora of tools in the background. They can also decide which tool to use and when to use it to answer your questions. In this tutorial...

Your team needs to solve a problem, and there's no clear solution path. Multiple approaches might work, but you're not sure which. Success isn't guaranteed. This is Research, not Development. And if you manage it like Development, things aren't going...

Foreign data wrappers (FDWs) make remote Postgres tables feel local. That convenience is exactly why FDW performance surprises are so common. A query that looks like a normal join can execute like a distributed system: rows move across the network, r...

How does the Internet really work? For many technical jobs it is important to understand computer networking. We just posted a massive 12-hour course that will give you a deep dive into computer networking. Here are the sections covered in this compr...

If you’re a developer working with containers, chances are Docker is your go-to tool. But did you know that there's a whole ecosystem of container runtimes out there? Some are lighter, some are more secure, and some are specifically built for Kuberne...

Have you ever wondered how YouTube notifies you when your favorite channel uploads a new video? Or how your email client alerts you when new messages arrive? These are perfect examples of the observer pattern in action. The observer pattern is a desi...

Performance problems in APIs rarely start as performance problems. They usually start as small design decisions that worked perfectly when the application had ten users, ten records, or a single developer testing locally. Over time, as traffic increa...

Embeddings have transformed how we search text, images, and code. Instead of matching keywords, you compare vectors, which are numerical representations that capture meaning. Similar items end up close together, making it easy to find matches. The sa...

Machine learning tasks usually start in a Python notebook, and for good reason. Notebooks make it easy to explore data, test ideas, and iterate quickly with minimal setup. They give teams a familiar place to experiment while questions remain open and...

This article explains how to design and implement your own circuit breaker in Spring Boot using explicit failure tracking, a scheduler-driven recovery model, and clear state transitions. Instead of relying solely on Resilience4j, we’ll walk through t...

A chess game is usually divided into three phases: the opening, middlegame, and endgame. In the opening phase, each player develops and sets up their pieces. In the middlegame, they plan attacks, execute different tactics and strategies to gain an ad...

If you've ever wondered how chat applications like Slack, Discord, or WhatsApp work behind the scenes, this tutorial will show you. You'll build a real-time chat server from scratch using Go, learning the fundamental concepts that power modern commun...

Today Quincy Larson interviews Robby Russell. Robby created the open-source project Oh My ZSH. Oh My Zsh is a framework for managing your Zsh configuration for your command line terminal. It's been extremely popular among developers for more than a d...

In most languages, the stack and heap are two ways a program stores data in memory, managed by the language runtime. Each is optimized for different use cases, such as fast access or flexible lifetimes. Go follows the same model, but you usually don’...

Extracting text from PDFs sounds simple until you try to do it. And it can be even more challenging for JavaScript developers, with various libraries to choose from and so on. I encountered this problem while I was building my SaaS app. I scoured thr...

Most React developers don’t break the data fetching process all at once. It usually degrades gradually, slowly. Traditionally, you may have used a useEffect here, a loading flag there, and an error state along with it to tackle data fetching. Moving ...

Learn to take a full-stack React, Go, and MongoDB application from local development to a fully containerized production environment. We just posted a full course on the freeCodeCamp.org YouTube channel that will help you master Docker orchestration,...

Nowadays, being able to present an idea, project, or achievement is a must-have skill. The ability to showcase and talk about your work can determine whether you’re getting that degree, funding, or approval. But while effective communication is impor...

For more than a decade, Heroku defined what “developer-friendly deployment” meant. Push code, forget servers, and focus on shipping features. That promise shaped an entire generation of platform-as-a-service products. In 2026, that landscape is chang...

Why Personalization Breaks Most AI Agents Personalization is one of the most requested features in AI-powered applications. Users expect an agent to remember their preferences, adapt to their style, and improve over time. In practice, personalization...

To protect your applications against threats, it’s helpful to understand the methods that attackers can use against you. We just posted a course on the freeCodeCamp.org YouTube channel that will help you master the fundamentals of cybersecurity and e...

Testing is one of those things that every developer knows they should do, but many put off until problems start appearing in production. If you’re building React applications with Vite, there's a testing framework that fits so naturally into your wor...

We just posted a course on the freeCodeCamp.org YouTube channel to help prepare you for the Certified Kubernetes Administrator Certification. This course is designed to provide a deep, practical understanding of Kubernetes administration, from founda...

Design patterns are proven solutions to common problems in software development. If you've ever found yourself writing repetitive object creation code or struggling to manage different types of objects, the factory pattern might be exactly what you n...

Writing code can be similar to writing tutorials. In both cases, you’ll typically need to create and work on multiple drafts before reaching the final version. In an ideal setting, you would write code for a feature, add that code to the staging area...

Hiring the right candidate starts with one time-consuming task: screening résumés. If you’ve ever posted a job opening, you know the pain of hundreds of applications in your inbox, leaving you to spend hours reviewing each résumé manually. In this ar...

A step-by-step guide to containerising a FastAPI application with Docker and deploying it to the cloud for consistent, production-ready delivery. Modern applications rarely live in isolation. They move between laptops, staging servers, and production...

In the world of big data, performance isn't just about bigger clusters – it's about smarter code. Spark is deceptively simple to write but notoriously difficult to optimize, because what you write isn't what Spark executes. Between your transformatio...

Feature flags are powerful tools that let you control which features are visible to users without deploying new code. They enable gradual rollouts, A/B testing, and instant feature toggles, which are all essential for modern software development. In ...

Your UI doesn’t “randomly” refuse to update. In most cases, it’s rendering cached data, which is data that was saved somewhere so the app doesn’t have to do the same work again. Caching is great for performance, but it becomes a pain when you don’t r...

Harvard University's CS50 is one of the most popular beginner computer science courses in the world. We just released the entire 25-hour CS50 course on the freeCodeCamp.org YouTube channel. This is the most recent version updated for 2026, with an al...

The AI landscape has shifted in 2026 from passive chatbots to proactive autonomous agents, with OpenClaw leading the charge as the most viral open-source project of the year. We just posted a comprehensive introduction to OpenClaw on the freeCodeCamp...

Ah, Bluetooth. The technology we all love to hate. It's like that one friend who's always just about to connect, but then... doesn't. For years, Android developers have been locked in a dramatic, often tragic, romance with Bluetooth. We've wrestled w...

As Flutter applications grow beyond a single mobile app, teams quickly encounter a new class of problems. Shared business logic begins to be copied across projects. UI components drift out of sync. Fixes in one app don’t propagate cleanly to others. ...

Modern systems generate huge volumes of logs. Application logs, server logs, and infrastructure logs often contain the first clues when something breaks. The problem is not a lack of data, but the effort required to read and understand it. Engineers ...

Have you ever noticed that your network connection sometimes feels fast and then suddenly slow, even when nothing obvious has changed? A request that takes 20 ms at one moment can take 80 ms the next, and sometimes it does not return at all. Terms li...

When you’re debugging a large React codebase, you might start to feel like a detective. Especially when you are looking for unexpected state changes, components that re-render when they like, or Context values that disappear into thin air without any...

As Flutter applications scale beyond a single market, language support becomes a critical requirement. A well-designed app should feel natural to users regardless of their locale, automatically adapting to their language preferences while still givin...

Many developers start learning programming by building simple projects like todo apps, calculators, and basic CRUD applications. These projects are useful at the beginning, as they help you understand how a programming language works and give you the...

Social media has become a vital tool for people and businesses to share ideas, promote products, and connect with their target audience. But creating posts regularly and managing schedules across multiple platforms can be time-consuming and repetitiv...

Today Quincy Larson interviews Tapas Adhikari. He's a software engineer who runs a firm of 20 developers who build projects for companies around the world. He's also a prolific teacher, having written 300 programming tutorials - including 47 for free...

Prioritization in product management is hardly about what metric takes precedence over the other. Of all the roles a product manager plays, one of the most difficult is deciding what to work on next. Why? Because everything feels urgent. Engineers wa...

Relational databases are used in many different types of software. We just posted a course on the freeCodeCamp.org YouTube channel that will help you learn relational database design from the ground up. This course covers SQL fundamentals, entity-rel...

Creating complex objects can get messy. You've probably written constructors with too many parameters, struggled with optional arguments, or created objects that require multiple setup steps. The builder pattern solves these problems by separating ob...

Bluetooth Low Energy advertising has always been one of those things developers “just use” until it breaks in subtle, painful ways. You set a name, throw in a UUID, maybe add some manufacturer data, and hope everything fits. For years, the unspoken r...

In software development, particularly object-oriented programming and design, object creation is a common task. And how you manage this process can impact your app's flexibility, scalability, and maintainability. Creational design patterns govern how...

In this tutorial, you'll learn how to build a complete RAG (Retrieval-Augmented Generation) search application from scratch. Your application will allow users to upload documents, store them securely, and search through them using AI-powered semantic...

Pipeline parallelism speeds up training of AI models by splitting a massive model across multiple GPUs and processing data like an assembly line, ensuring no single device has to hold the entire model in memory. This course teaches pipeline paralleli...

Relational databases are used all the time in software development. We just published a course on the freeCodeCamp.org YouTube channel that will help you learn relational database design from the ground up. This course covers SQL fundamentals, entity...

Large language models are good at answering questions, but they have one big limitation: they don’t know what is inside your private documents. If you upload a PDF like a company policy, research paper, or contract, the model cannot magically read i...

In software engineering, sometimes you need only one instance of a class across your entire application. Creating multiple instances in such cases can lead to inconsistent behavior, wasted memory, or resource conflicts. The Singleton Design Pattern i...

Every day, we learn something new about generative AI applications – how they behave, where they shine, and where they fall short. As Large Language Models (LLMs) rapidly evolve, one thing becomes increasingly clear: selecting the right model for you...

Have you ever needed a method to return different types depending on the situation? Perhaps a payment processor that returns different payment types, an order that can be in various states with different data, or better, a file loader that handles mu...

PDF files are everywhere. They’re used for reports, invoices, bank statements, research papers, and legal documents. While PDFs are easy to read for humans, they’re not easy to work with in code. Extracting text, splitting pages, or merging files oft...

Today Quincy Larson interviews Sumit Saha, a software engineer and prolific teacher on YouTube. Sumit is based in Dhaka, Bangladesh, where he runs a developer agency building projects for clients throughout Asia. We talk about: How the hunger for le...

The singleton pattern ensures that a class has exactly one instance throughout your application. You've probably seen it in configuration managers, database connections, or logging systems. While singletons seem useful, they often create more problem...

Building AI today is about more than just a clever prompt. If you really want to move from playing with standalone tools to creating integrated systems that actually work with your data, our new crash course on the freeCodeCamp.org YouTube channel is...

These days it feels almost impossible to keep up with tech news. I step away for three days, and suddenly there is a new AI model, a new framework, and a new tool everyone says I must learn. Reading everything no longer scales, but I still want to st...

Dynamic programming (DP) is often considered one of the most intimidating topics in coding interviews. It has a reputation for being abstract and counterintuitive, but it doesn't have to be. We just published a comprehensive Dynamic Programming cours...

The "liminal space" aesthetic of the Backrooms has become a staple of modern indie horror. If you’ve ever wanted to create your own unsettling, claustrophobic experience, the latest course on the freeCodeCamp.org YouTube channel is your perfect start...

Execution Context is one of the most fundamental yet most misunderstood concepts in JavaScript. It defines how JavaScript code is evaluated and executed, and it plays a central role in determining how variables, functions, and scope behave. Many core...

Platforms like Vercel, Netlify, and Render simplify deployment by handling infrastructure for you. In this tutorial, we’ll step one layer deeper and work directly with AWS to understand the building blocks behind these platforms. You'll take a small ...

As Flutter developers, we know that Flutter’s “batteries included” philosophy has long been its superpower. Built on the simple premise to "paint every pixel," the framework shipped with everything needed to build a real app out of the box: a renderi...

Today Quincy Larson interviews Mike McQuaid. He's a software engineer who previously worked at GitHub, and now serves as lead maintainer of Homebrew, a Mac package manager used by tens of millions of developers. He's based in Edinburgh, Scottland. He...

If you're learning JavaScript, you've probably heard the term "closure" at some point. In many developers' experience, just hearing this word can trigger anxiety. In nearly 17 years of programming experience, I've noticed that closures are one of the...

In this tutorial, you’ll walk through a complete data analysis project using the HR Analytics dataset by Saad Haroon on Kaggle. You’ll start by loading and cleaning the data, then explore it visually using boxplots with ggplot2. Finally, you’ll learn...

Blue-green deployments are celebrated for enabling zero-downtime releases and instant rollbacks. You deploy your new version (green) alongside the current one (blue), switch traffic over, and if something goes wrong, you switch back. Simple, right? N...

We just posted a Kubernetes Operator course on the freeCodeCamp.org YouTube channel. You will learn how to extend Kubernetes by building your own custom operators and controllers from scratch. You’ll go beyond simply using Kubernetes and start treati...

Choosing a GPU for your AI workload shouldn't be complicated, but it often feels that way. You're weighing specs you don't fully understand, comparing prices that seem arbitrary, and wondering if you're about to waste thousands on GPUs you don't need...

What happens when you lock over 2,500 ambitious developers in a massive science museum for an entire weekend? We posted a documentary on the freeCodeCamp.org YouTube channel that takes you to the heart of Cal Hacks 2025, held at the iconic former Exp...

Finding the right embedding model for your specific data can often feel like guesswork, but it doesn't have to be. While generic benchmarks provide a baseline, they rarely reflect how a model will perform on your unique datasets and niche terminology...

Databases are a crucial tool because they store the data that power our day-to-day lives. Databases are designed to match the real world as much as possible, so they store data of different forms, about different things, just as it is in the world. T...

Processing payroll payments is an important operation for any business. When you need to pay employees simultaneously, you can't afford to have your server hang, get blocking errors, or timeout while waiting for each payment to complete. Building a p...

These days, developers are increasingly preferring utility-first CSS frameworks like Tailwind CSS to help them build fast, scalable, and highly customizable user interfaces. In this article, you’ll learn what the tailwind-sidebar NPM package is, how ...

Over 80% of Fortune 100 companies use Apache Kafka. That's not surprising, as Kafka has revolutionized how we build real-time data pipelines and streaming applications. If you're working in software engineering today, chances are you've encountered K...

NixOS is a Linux distribution based on the Nix package manager and the Nix language. It’s first stable release was in 2013, and it uses a declarative, reproducible system configuration that allows atomic upgrades and rollbacks. The Nix language is a ...

Turning written blog posts into audio is a simple way to reach more people. Many users prefer listening during travel or workouts. Others enjoy having both reading and listening options. With OpenAI’s text-to-speech models, you can build a clean ser...

If you've worked with big data or analytics platforms, you've probably heard about ORC files. But what exactly are they, and how can you work with them in Python? In this tutorial, I'll walk you through the basics of reading, writing, and manipulatin...

For years, developers have been told that coding was their primary job. They were encouraged to write clean code, learn tools, understand frameworks, and ship features faster. But in the actual world of Software Engineering, especially in product-foc...

If you're learning Go and you’re already familiar with the idea of unit testing, the main challenge is usually not why to test, but how to test in Go. Go takes a deliberately minimal approach to testing. There are no built-in assertions, no annotatio...

Have you ever updated your backend API property name but neglected to also update the frontend? I'm sure you have. When this occurs, it leads to production crashes and unhappy customers, plus you've wasted your entire week fixing the problem. To reso...

Most AI tools require you to send your prompts and files to third-party servers. That’s a non-starter if your data includes private journals, research notes, or sensitive business documents (contracts, board decks, HR files, financials). The good new...

Most financial apps store your sensitive data on remote servers. This requires you to trust a company with your records and rely on their service staying online. But if you build a local-first application, you can keep your data on your own machine i...

An API rate limiter is a server-side component of a web service that limits the number of API requests a client can make to an endpoint within a period of time. For example, X (formerly known as Twitter) limits the number of tweets that a specific us...

Today Quincy Larson interviews Zubin Pratap, a software engineer and manager from Melbourne, Australia. After nearly two decades working as a corporate lawyer, he taught himself programming using freeCodeCamp.org. Within two years, he landed a job as...

Artificial intelligence is changing how we build software. Just a few years ago, writing code that could talk, decide, or use external data felt hard. Today, thanks to new tools, developers can build smart agents that read messages, reason about them...

A few years back, choosing an AI model was simple. You pick the most capable one you can afford and move on. But today, that approach no longer works. Today, teams use AI across many parts of a system. Customer-facing features. Internal tooling. Rese...

Shopify powers more than a million online stores around the world. Many store features you see every day, such as discounts, bundles, and order fulfillment are built using apps. These apps are created by developers to extend Shopify and solve real p...

If you’re a developer, you’ll likely want to use AI to boost your productivity and help you save time on menial, repetitive tasks. And nearly every recruiter these days will expect you to understand how to work with AI tools effectively. But there’s ...

React makes it easy to build UIs, but building fast React apps is a different skill altogether. We just posted a hands-on, real-world React Performance Optimization course on the freeCodeCamp.org YouTube channel. You’ll learn how React actually re-re...

Did you know that every data scientist who builds a complex neural network starts with a fundamental question, “How does the output change when the input changes?“ A straight line equation y = ax+b answers it in the simplest way possible. y can incre...

As a Flutter developer who’s building a cloud-based ecosystem for digital media lifecycle management, I’m constantly looking for ways to speed up the transition from idea to prototype. In November 2025, Google launched antigravity, a new interactive ...

Many developers think that “real-time” is about Websockets, Live data, or instant refreshes on web application dashboards. And although these concepts are closely related to what real-time means, the systems engineering definition is a bit different....

Every time you open a website, your device talks directly to another server on the internet. Your IP address, location, and basic network details are visible to that server. In many cases, this is fine. But there are situations where you may want m...

"To understand is to perceive patterns." - Isaiah Berlin This is not a math book filled with complex formulas, theorems, and concepts that are hard to grasp. Instead, it’s a detailed guide where we’ll break complex ideas down into simpler terms. Eve...

Learn how to build agentic AI workflows. We just posted a course on the freeCodeCamp.org YouTube channel that provides a comprehensive overview of agentic AI, defining agents as software entities that use LLMs to perceive environments, make decisions...

OAuth 2.0 is an industry-standard authorization framework allowing third-party apps to access user data on another service (like Google or Facebook) without sharing passwords, instead using temporary, limited-scope access tokens for delegated access,...

We just posted a comprehensive music production course on the freeCodeCamp.org YouTube channel that bridges the gap between basic theory and professional execution. Miguel guides you through the entire lifecycle of a song using tools like FL Studio. ...

Have you ever wanted to add an AI-powered chatbot to your website, like Intercom or Drift, without paying high monthly fees? In this tutorial, you'll learn how to build a fully functional, embeddable AI chatbot widget using Cloudflare's serverless st...

You can use R as a powerful tool for data analysis, data visualization, and statistical modelling. In this guide, you’ll learn how to load real-world data into R, visualize patterns using ggplot2, build simple linear and logistic regression models, a...

While containers are quite lightweight and provide various benefits, it can be challenging to decide how best to deploy them. There are a number of ways to deploy and run Docker containers. But some are best for orchestrating and managing containers,...

Hi, I’m Ilyas. I’m a web developer, and this is my story about how I struggled with interviews for a long time and what finally helped me break through. I’ll talk about what failing basic interview questions taught me about recall, preparation, and s...

2025 has been an amazing year for the global freeCodeCamp community. And we’re thrilled to cap it off with the launch of several Christmas Gifts for you: freeCodeCamp's Python certification freeCodeCamp's JavaScript certification (Version 10) free...

In standard app development, the User Interface (UI) is static. You write code for a button, compile it, and it remains a button forever. GenUI flips this model on its head. With GenUI, Google’s Generative UI SDK, your application's interface becomes...

Vercel AI SDK is a TypeScript-first toolkit for building AI features. It streamlines text generation, embeddings, and structured outputs. We just posted a course on the freeCodeCamp.org YouTube channel that will teach you to use the Vercel AI SDK to ...