Glossary

The portion of a web page visible without scrolling

The practice of making websites usable by as many people as possible

A UI pattern with collapsible sections of content

Application Programming Interface - A set of rules and protocols that allows different software applications to communicate with each other

Accessible Rich Internet Applications - A set of attributes to make web content more accessible

A methodology for creating design systems with five distinct levels: atoms, molecules, organisms, templates, and pages

Backend as a Service - Cloud service providing backend functionality

Behavior-Driven Development - An extension of TDD that emphasizes collaboration and behavior specification

A deployment strategy that reduces downtime by running two identical production environments

A navigation aid showing the user's location in a website hierarchy

Combining multiple files into a single file to reduce HTTP requests

Gradually rolling out changes to a small subset of users before full deployment

A UI component that cycles through a set of content items

Content Delivery Network - A geographically distributed network of servers that deliver web content to users based on their location

Continuous Integration/Continuous Deployment - Automated processes for testing and deploying code

Cumulative Layout Shift - Measures visual stability

Splitting code into smaller chunks that can be loaded on demand

A reusable, self-contained piece of UI in modern web frameworks

A pattern where components work together to form a complete UI

A way to pass data through the component tree without having to pass props manually at every level

Automatically deploying code changes to production after passing automated tests

The practice of automatically testing and merging code changes frequently

Small pieces of data stored in the browser, sent with every HTTP request

A set of metrics that measure user experience: LCP, FID, and CLS

Cross-Origin Resource Sharing - A mechanism that allows restricted resources to be requested from another domain

The minimum CSS required to render the above-the-fold content

Create, Read, Update, Delete - The four basic operations of persistent storage

Client-Side Rendering - Rendering web pages in the browser using JavaScript

Cross-Site Request Forgery - An attack that tricks a user into executing unwanted actions on a web application

Call to Action - An element that prompts users to take a specific action

Removing code that is never executed or used

Limiting the rate at which a function can fire, waiting for a pause in events

A collection of reusable components and guidelines for consistent design

Domain Name System - The phonebook of the internet, translating domain names to IP addresses

A platform for developing, shipping, and running applications in containers

A UI element that displays a list of options when clicked

End-to-End Testing - Testing the complete flow of an application from start to finish

Running code closer to users by executing it on servers distributed globally

A static code analysis tool for identifying problematic patterns in JavaScript code

A technique to enable or disable features without deploying new code

First Input Delay - Measures interactivity

A distributed version control system for tracking changes in source code

A query language for APIs that allows clients to request exactly the data they need

A content management system that provides content via an API without a built-in frontend

A component that provides logic and state management without dictating UI

The first section of a webpage, typically featuring a large image or video

Higher-Order Component - A function that takes a component and returns a new component

Functions that let you use state and other React features in functional components

The process of attaching JavaScript event handlers to server-rendered HTML

A low-level API for client-side storage of significant amounts of structured data

A web design pattern where content loads continuously as the user scrolls

Testing how different parts of an application work together

Incremental Static Regeneration - Updating static pages after build time without rebuilding the entire site

JavaScript, APIs, and Markup - Modern web development architecture based on client-side JavaScript, reusable APIs, and prebuilt markup

JSON Web Token - A compact, URL-safe means of representing claims to be transferred between two parties

An open-source container orchestration platform

Deferring the loading of non-critical resources until they're needed

Largest Contentful Paint - Measures loading performance

Web storage that allows JavaScript to store key-value pairs in the browser

An optimization technique that stores the results of expensive function calls

An architectural style that structures an application as a collection of loosely coupled services

Software that acts as a bridge between an operating system or database and applications

Removing unnecessary characters from code without changing functionality to reduce file size

Designing for mobile devices first, then scaling up to larger screens

A dialog box that appears on top of the current page

A single repository containing multiple distinct projects

Open Authorization - An open standard for access delegation, commonly used for token-based authentication

Object-Relational Mapping - A technique for converting data between incompatible type systems (e.g., database and objects)

Dividing content into discrete pages

Code that implements a feature on web browsers that don't support it natively

An opinionated code formatter

Properties passed to a component to customize its behavior or appearance

Progressive Web App - Web applications that provide a native app-like experience

A predictable state container for JavaScript apps

A technique for sharing code between components using a prop whose value is a function

An approach to web design that makes web pages render well on various devices and screen sizes

Representational State Transfer - An architectural style for designing networked applications using HTTP requests

Software as a Service - Software delivery model where applications are hosted and licensed on a subscription basis

Search Engine Optimization - The practice of increasing the quantity and quality of traffic through organic search results

A cloud computing execution model where the cloud provider manages the server infrastructure

A script that runs in the background, separate from a web page, enabling features like push notifications and offline functionality

Similar to localStorage but data is cleared when the page session ends

A placeholder UI that mimics the layout of content while it's loading

Single Page Application - A web application that loads a single HTML page and dynamically updates content

A code injection technique that exploits security vulnerabilities in an application's database layer

Static Site Generation - Pre-rendering pages at build time to serve as static files

Server-Side Rendering - Rendering web pages on the server before sending them to the client

Data that changes over time in an application

Test-Driven Development - A development approach where tests are written before code

Limiting the rate at which a function can fire, executing at regular intervals

A small, temporary notification that appears on screen

Converting source code from one programming language to another at a similar abstraction level

A term for eliminating dead code from JavaScript bundles

Time to First Byte - Measures the time between the request and the first byte of response

Time to Interactive - Measures how long it takes for a page to become fully interactive

A typed superset of JavaScript that compiles to plain JavaScript

User Interface - The visual elements through which users interact with a product

Testing individual units or components of code in isolation

User Experience - The overall experience of a person using a product

A programming concept where a virtual representation of the UI is kept in memory and synced with the real DOM

Web Content Accessibility Guidelines - Standards for making web content accessible

A way to run scripts in background threads in web browsers

A binary instruction format for a stack-based virtual machine that runs in web browsers

A static module bundler for JavaScript applications

Cross-Site Scripting - A security vulnerability that allows attackers to inject malicious scripts into web pages

A small, fast, and scalable state management solution