Glossary

An AI that can take actions on its own — writing files, running commands, browsing the web — rather than just answering questions. Claude Code and Cursor's agent mode are examples. You describe the goal; the agent figures out the steps.

A set of rules that lets two pieces of software talk to each other. When your app needs data from another service (like weather or payments), it uses an API to ask for it. Think of it like a waiter — you tell the waiter what you want, the waiter tells the kitchen, the kitchen sends back your food.

The overall plan for your entire application — what it does, what the major pieces are, and how they connect. Created before you start building. Like a blueprint for a house.

Verifying who someone is. When you log in with a username and password, that's authentication. Different from authorization (what you're allowed to do).

Determining what someone is allowed to do after they've logged in. Authentication is "who are you?" Authorization is "what can you do?"

A way of writing code that waits for slow operations (like fetching data from a server) without freezing everything else. "Async" marks a function as one that might wait. "Await" says "pause here until this finishes." You'll see these everywhere in AI-generated code.

The part of an app that runs on a server — handling data, logic, and database operations. Users never see the backend directly. If a restaurant is the metaphor, the backend is the kitchen.

A way of describing how fast or slow code runs as the amount of data grows. O(n) means time grows proportionally. O(n²) means it gets dramatically slower. You don't need to calculate it — just recognize when AI builds something that will choke on real data.

Repetitive, standard code that shows up in nearly every project. Setting up a server, configuring a database connection, creating a basic HTML page — all boilerplate. AI is great at generating this for you.

A parallel copy of your project where you can make changes without affecting the main version. If the changes work, merge them back. If not, throw the branch away.

An error in code that causes unexpected behavior. Could be a typo, a logic mistake, or an incorrect assumption.

The process of converting your source code into something that can actually run. Some projects need a build step (compiling, bundling, optimizing) before they work. "Run the build" or "the build failed" refers to this process.

Temporary storage that keeps frequently used data close at hand so the system doesn't have to fetch it every time. Your browser caches images so pages load faster on repeat visits.

A template for creating objects. It defines what information an object will hold (variables) and what actions it can perform (functions). A "User" class is the blueprint — each actual user is an object created from that class.

A command-line AI coding tool from Anthropic. It understands your entire project, creates and edits files, runs commands, and works autonomously on larger tasks. Works alongside an IDE like Cursor — think of it as an autonomous contractor you bring in for bigger jobs.

A way of interacting with software by typing text commands instead of clicking buttons. The terminal is a CLI. Many developer tools (Git, Docker, npm) are CLI tools.

The device or browser that a user interacts with directly. When you visit a website, your browser is the client. It sends requests to the server (backend) and displays the responses. "Client-side" means code that runs in the browser.

A snapshot of your project at a specific point in time. Each commit has a message describing what changed. You can always go back to any previous commit.

When a program handles multiple tasks that overlap in time. Like a chef rotating between three dishes. Different from parallelism, where multiple things happen at the same instant.

A self-contained package that includes your app and everything it needs to run. Runs the same way everywhere, regardless of the host computer. A shipping container for software.

Create, Read, Update, Delete — the four basic operations for managing data. Almost every app is built around CRUD.

A reusable, self-contained piece of a user interface. A navigation bar, a login form, a product card — each is a component. Modern web development (React, Vue) is built around composing small components into full pages.

The language that controls how a website looks — colors, fonts, spacing, layout. HTML defines the content; CSS defines the appearance. AI generates CSS for you, but knowing what it is helps when things look wrong.

An AI-powered IDE (code editor) built on VS Code. Has a chat panel, inline editing, tab completion, and agent mode. Supports multiple AI models. The recommended starting IDE for vibe coding.

An organized system for storing and retrieving data permanently. User accounts, orders, messages — all live in a database. A very structured, instantly searchable filing cabinet.

Finding and fixing errors in code. Part detective work, part elimination. One of the most important skills whether you write code or direct AI.

Code your project relies on that was written by someone else. Libraries that handle common tasks like sending emails or formatting dates. If a dependency breaks, your app is affected.

Putting your app on the internet so other people can use it. Going from localhost to a real URL.

A temporary server on your own computer that lets you see and test your app in a browser during development. Only you can see it.

A tool that packages your app and everything it needs into containers that run the same way on any computer. Solves the "it works on my machine" problem. Essential for consistent development environments.

A tool for running multi-container Docker setups with a single command. Your app might need a web server, a database, and a cache — Docker Compose starts all of them together from one configuration file.

The browser's internal representation of a web page as a tree of elements. When JavaScript changes the DOM, the page updates. "Manipulating the DOM" means changing what the user sees on screen.

A specific URL in an API that does one specific thing. "/users" returns a list of users. "/users/123" returns one specific user.

The setup where your code runs. "Development" is your local machine. "Staging" is a test server. "Production" is the live version real users see.

A configuration file that stores sensitive information (API keys, database passwords, secret tokens) outside your code. Keeps secrets out of Git so they don't accidentally end up on GitHub. Never commit your .env file.

Something that happens in your app that code can respond to. A click, a page load, a form submission. Your code "listens" for events and runs functions when they occur.

The part of an app the user sees and interacts with. Buttons, forms, layouts. The frontend talks to the backend to get and save data. The dining room to the backend's kitchen.

A pre-built structure that gives you a starting point for building an app. React, Next.js, Django, Express — each provides patterns and tools so you're not starting from zero. AI often suggests a framework when you describe what you want to build.

Both the frontend and backend together. A "full-stack app" handles everything from the user interface to the database. A "full-stack developer" works on both sides. Vibe coders are often building full-stack without realizing it.

An action that takes information, does something with it, and produces a result. Functions are verbs — they make things happen. "Send notification" and "calculate total" are functions.

A version control system that tracks every change to your project and lets you go back to any previous version. Like Google Docs version history, but for your entire project.

A website that stores your Git projects in the cloud. Git is the save system; GitHub is the cloud storage where saves get backed up.

A service that runs your app on the internet so anyone can access it. Vercel, Netlify, Railway, AWS — all hosting providers. Your app lives on their servers and they give you a URL.

A feature that automatically updates your app in the browser when you save a file. No manual refresh needed.

The language that defines the structure and content of web pages. Headings, paragraphs, images, links, forms — all HTML. CSS controls how it looks; JavaScript controls how it behaves. Every website is built on HTML.

The protocol browsers and servers use to communicate. HTTPS adds encryption. The "S" stands for secure — always use it for anything with user data.

The app where you write and manage code. Your home base. Cursor and VS Code are popular IDEs with built-in terminals, file browsers, and AI.

A read-only template used to create Docker containers. If a container is a running app, an image is the blueprint it was created from. You download images and run them as containers.

The programming language of the web. Every website uses JavaScript for interactivity — clicking buttons, loading data, animating elements. Also used on servers (Node.js). The most common language AI generates for web apps.

A standard format for structuring data as text. Used everywhere — APIs, config files, databases. Looks like label-value pairs: {"name": "Sarah", "age": 28}.

A unique identifier that grants access. API keys identify your app to a service. Database keys uniquely identify records (like a user ID).

Pre-written code that handles a common task so you don't have to build it yourself. Need to send emails? There's a library for that.

Automatically checking code for style issues, potential bugs, and inconsistencies. A linter is like spell-check for code. Most IDEs run linters in the background and show warnings as you work.

Your own computer acting as a web server. Type "localhost" in a browser and it talks to your machine instead of the internet. How you run and test your app during development.

Recording what your app is doing as it runs. Like a flight recorder for software. When something goes wrong, logs tell you what happened, when, and in what order. Essential for debugging.

A simple text formatting language. Use # for headings, ** for bold, - for lists. README files, documentation, and many chat interfaces use Markdown. Much simpler than HTML.

Combining changes from one branch into another. When experimental changes work, you merge them into the main project.

Code that sits between a request coming in and a response going out. Like a security guard — every request passes through, and middleware can check credentials, log activity, or modify data.

A controlled change to your database structure. Adding a column, creating a table, reorganizing data. Version control for your database.

The trained AI system that generates responses and code. GPT-4, Claude, Gemini — each is a model. Different models have different strengths. Cursor lets you switch between models depending on the task.

A way to run JavaScript outside of a browser — on a server or your local machine. Most web development tools (npm, build scripts, development servers) run on Node.js. You'll install it early in your setup.

Node Package Manager — a tool for installing and managing JavaScript libraries. "npm install" downloads everything your project needs. package.json lists the dependencies.

A bundle of related variables and functions. A "User" object holds a name, email, password (variables) and can log in, log out (functions). Objects are nouns with superpowers.

Software whose code is publicly available for anyone to view, use, and modify. Most developer tools, libraries, and frameworks are open source. VS Code, React, Docker — all open source.

A bundle of code published for others to use — essentially a library with a name, version, and installation instructions. npm packages, pip packages — when AI adds a dependency to your project, it's installing a package.

A file in JavaScript projects that lists all the packages (dependencies) the project needs, plus project metadata and scripts. When you run "npm install," npm reads this file to know what to download.

Multiple tasks running at literally the same time on different processors. Two chefs each cooking a dish simultaneously. Different from concurrency (one chef rotating between dishes).

A number identifying a specific service on a computer. Localhost is the building address; the port (3000, 8080) is the apartment number.

The live version of your app that real users interact with. Bugs here affect real people, which is why you test first.

The text instruction you give to AI. In vibe coding, your prompt is how you tell AI what to build. The quality of your prompt directly determines the quality of AI's output.

The skill of writing effective prompts that get good results from AI. Being specific, providing context, giving examples, and describing the full architecture are all prompt engineering techniques.

Downloading changes from GitHub to your local machine. The opposite of push. "Pull before you start working" ensures you have the latest version.

Uploading your local commits to GitHub. Backs up your work and makes it available from other computers.

A popular programming language known for being readable and beginner-friendly. Widely used for backends, data science, automation, and AI. One of the most common languages AI generates code in.

A request for specific data from a database. "Show me all users who signed up this month" is a query. SQL is the most common query language.

A bug where two things try to use or change the same data simultaneously, and the result depends on which finishes first. Two people booking the last seat at the same time.

A popular JavaScript framework for building user interfaces, created by Meta. Organizes UI into reusable components. One of the most common frameworks AI uses when building web apps.

A file (usually README.md) that explains what a project is, how to set it up, and how to use it. The first thing people see when they find your project on GitHub. Written in Markdown.

Restructuring code without changing what it does. Same app from the user's view, cleaner code underneath. Like reorganizing a closet.

A project folder tracked by Git, including all files and complete version history. A GitHub repo is the cloud copy.

A design that adjusts to look good on any screen size — phone, tablet, desktop. A responsive website rearranges its layout based on how wide the browser is.

A common pattern for building APIs. Uses standard HTTP methods: GET to read data, POST to create, PUT to update, DELETE to remove. Most APIs AI builds follow REST conventions.

Mapping a URL to a specific page or action. When someone visits /about, the router shows the About page. When they visit /users/123, it shows user 123's profile. Routing is how your app knows what to display.

The environment where code actually executes. Node.js is a JavaScript runtime. Python is its own runtime. "Runtime error" means something went wrong while the code was running (as opposed to while it was being built).

Auto-generating the basic structure of a project or feature. "Scaffold a new React app" creates all the starter files and folders. AI does this for you when you describe what you want to build.

The structure of a database — what tables exist, what columns each has, what types of data they hold. A spreadsheet template that defines the headers before data is entered.

A collection of tools, libraries, and documentation that makes it easier to build for a specific platform or service. The Stripe SDK makes it easy to add payments. The Firebase SDK handles authentication.

A computer that provides services to other computers. Web servers deliver web pages. Database servers store and retrieve data. When you deploy your app, it runs on a server. During development, your own computer acts as a server (localhost).

Code where everything is tangled together with no clear structure. When one thing breaks, everything breaks, and nobody can tell where the problem is.

Structured Query Language — the standard language for talking to databases. You don't need to write SQL yourself, but understanding what it does helps when AI generates it.

All the data your app is holding at any given moment. Login status, cart items, selected tab — all state. Managing it well is one of the hardest parts of building software.

The combination of technologies used to build an app. "MERN stack" means MongoDB, Express, React, Node.js. When AI asks what stack you want, it's asking which technologies to use together.

A test environment that mimics production but isn't public. You deploy to staging to test before going live. Catches problems that only appear in a real server environment.

The specific rules for how code must be written in a given language. Like grammar for code. A missing semicolon or bracket is a syntax error. You don't write syntax — but when AI's code has a syntax error, it won't run at all.

A text-based interface for giving commands to your computer. Instead of clicking, you type. Your IDE has one built in (Ctrl+` in Cursor).

Writing code that checks whether your other code works correctly. Tests catch bugs before users do.

A string of characters that proves identity or grants access. Like a wristband at a concert — your browser shows it with every request so the server knows you're authenticated.

JavaScript with added type checking. Instead of just saying a variable holds "something," TypeScript says it holds "a string" or "a number." Catches bugs before code runs. Many AI-generated projects use TypeScript.

Everything the user sees and interacts with. Buttons, menus, forms, text, images. "The UI" refers to the visual design and layout of your app.

A test that checks one small piece of code in isolation. Does this one function return the right result? Fast, focused, catches bugs early.

A web address. "https://bettervibecoding.com/guides" is a URL. It tells the browser which server to talk to and which page to request. In your app, every page has a URL defined by your routing.

How it feels to use an app — not just how it looks, but whether it's intuitive, fast, and pleasant. Good UX means users can accomplish what they came to do without frustration.

A piece of information software remembers. A labeled container holding a value — "user name: Sarah" or "task count: 7." Variables are nouns.

A system that tracks every change to your project and lets you go back to any version. Git is the most popular. Essential for undoing mistakes and backing up work.

Building software by describing what you want in plain language and letting AI write the code. You're the director; AI is the hands on the keyboard.

A free, open-source IDE from Microsoft. Hugely popular with a massive extension ecosystem. Cursor is built on VS Code, so they share the same interface. A solid alternative if you don't use Cursor.

An application that runs in a web browser instead of being installed on your device. Gmail, Trello, Figma — all web apps. Most vibe coding projects produce web apps.

An automatic notification from one system to another when something happens. Instead of constantly asking "anything new?", the other system tells you. A text when your package arrives vs. checking the doorstep every hour.