Web Development Glossary: 93 Essential Terms

This web development glossary brings together 93 terms you’ll hear when building or managing a website. Arranged A–Z, the glossary covers essentials like APIs, CMSs, hosting, security, and accessibility. The clear explanations are designed to help beginners feel confident while also giving business leaders the language to ask better questions, draft stronger RFPs, and avoid delays. Start exploring the terms to make your web projects easier to plan and manage.

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75 Web Development Terms to Know

Knowing these terms is useful beyond definitions. It makes it easier to read proposals with confidence, understand what vendors are promising, and keep project conversations focused on business goals instead of getting lost in technical jargon. Stay in the loop about the key terms to know.

#

• 301 Redirect: A permanent redirect from one URL to another.
• 404: An error message that a user sees when what was requested can’t be found.

A

• Accessibility: The practice of making websites usable for people with disabilities by following standards such as WCAG 2.2. This involves ensuring sites are perceivable, operable, understandable, and robust. Techniques may include semantic HTML and ARIA roles to support screen readers, keyboard navigation, and low-vision users. Testing tools like Google Lighthouse can also flag accessibility issues, though full accessibility reviews also require manual and assistive technology testing.
• ADA Compliance: The Americans with Disabilities Act (ADA) requires businesses and organizations open to the public to make their digital content accessible. While the law doesn’t spell out exact technical rules, most compliance is measured against WCAG guidelines, which are built on four principles: Perceivable, Operable, Understandable, and Robust.
• AJAX: Short for Asynchronous JavaScript and XML, AJAX is a technique that lets web pages update parts of content in the background without reloading the entire page. It’s commonly used for features like live search, chat apps, and form validation.
• Algorithm: A set of instructions that a computer follows to automatically solve a problem or carry out a task. In web development, algorithms are used for things like sorting lists, filtering content, powering search, and securing data.
• API (Application Programming Interface): A set of rules that allow different software systems to communicate. An API might let a website connect with a payment system or a mobile app pull data from a server. Common approaches include REST, GraphQL, and gRPC. Most modern sites rely on APIs to separate what users see on the front end from the systems that handle data and logic on the back end.
• Application: An app is a program designed to perform functions.
• Attribute: Information about a component in a website build.

B

• Backend: The behind-the-scenes operations that keep a website running, which can include coding and plugins.
• Backup: The process of creating a copy of site data.
• Bandwidth: The measure of how much information can pass through depending on the connection.
• Bootstrap: An open-source CSS and JavaScript framework used to build responsive, mobile-first websites. It provides ready-made components such as grids, buttons, and navigation menus, allowing developers to speed up design and keep layouts consistent.
• Bounce Rate: The percentage at which a person leaves your website without interacting with a page.
• Browser: The program used to access the web. Examples include Chrome, Safari, & Firefox.
• Bug: An error or flaw in the website.

C

• Cache: The storage of certain features and elements to help with faster load times from repeated site visitors.
• CMS (Content Management System): A tool for running a website’s content. With a CMS, you don’t need to write code just to add a new page, update text, or swap out an image. WordPress is a common example, though platforms like Drupal and Joomla are also widely used. For a business, the choice of CMS shapes how easy it is for staff to keep information current, how secure the site is, and how much it costs to maintain.
• Content Delivery Network (CDN): A network of servers placed in different geographic locations that deliver website content from the server closest to each user. CDNs help reduce latency, speed up page loads, and improve reliability during traffic spikes.
• Cookies: Small pieces of data stored in a user’s browser, often used for sessions and tracking. In recent years, browsers have added SameSite rules and are phasing out third-party cookies. Many sites now rely more on local storage and newer privacy-focused APIs.
• Crawl: Search engines send bots to gather intel on published web pages to determine what should be displayed or removed.
• CRM (Customer Relationship Management): The software and apps used to gather, analyze, and maintain information on prospects.
• CSS (Cascading Style Sheet): The code that communicates to the browser about how to display a webpage.

D

• Database: An ordered system for storing a set of information resources.
• DevOps: A collection of practices that bring software development (Dev) and IT operations (Ops) together. DevOps emphasizes automation, continuous integration/continuous deployment (CI/CD), and close collaboration to shorten release cycles and improve reliability.
• Domain: The address for a website.
• DNS (Domain Name System): A hierarchical naming system built for any resource connected to a private network or the Internet.

E

• E-Commerce: A type of website where consumers can purchase products online.
• End User: A person who ultimately uses and visits the website.

F

• Firewall: A system to protect a secure network from an unsecured network.
• Fonts: The character set within the typeface that refers to a particular size and style.
• Framework: Suite of programs used in website development that lays the groundwork for programming languages.
• Frontend: The part of the website that users see. Frontend development focuses on classic website design elements.
• FTP (File Transfer Protocol): A method of exchanging files from one computer to another – this is how websites are uploaded to the Internet.
• Full-stack: A developer who works across all layers of a web application—the front end (what users see), the back end (server logic and APIs), and the database. Full-stack developers know a mix of languages and frameworks that let them connect these parts and ship complete features. Many teams rely on them for smaller projects or early prototypes where one person can manage the full build.
• Functionality: Features that make it easier for users to navigate a platform.

G

• GUI (Graphical User Interface): The image of how a website is laid out and meant to be interacted with.

H

• Homepage: The default page of a site.
• Hosting: Refers to a web server where files for your website are stored.
• HTML: The standard markup language used to structure content on the web.  It defines elements such as headings, paragraphs, links, and images, working alongside CSS for styling and JavaScript for interactivity. Every website uses HTML, with clean structure helping to support accessibility, search engine optimization, and long-term site maintenance.
• HTTP (Hypertext Transfer Protocol): The standard protocol for transferring data on the web. It defines how messages are formatted and transmitted, and how servers and browsers should respond to requests. Most modern sites now use HTTPS, a secure version of HTTP that encrypts data in transit.
• HTTPS (Hypertext Transfer Protocol Secure): The secure version of HTTP used to send data between a browser and a server. HTTPS adds encryption through TLS (Transport Layer Security), which scrambles information so it can’t be read if intercepted. Today, most browsers warn users if a site is still using plain HTTP instead of HTTPS.

I

• Information Architecture: The practice of organizing complex information in a clear way.
• IP Address: Identifies a network or device on the Internet. 

J

• Javascript: A programming language that makes web pages interactive. It runs directly in all major browsers and enables features like menus, buttons, animations, forms, and dynamic updates without reloading the page. . JavaScript works with HTML and CSS to create modern websites, and most frameworks and libraries — such as React, Angular, or Vue — are built on it. Because nearly every site uses JavaScript, it plays a central role in performance, user experience, and how quickly features can be built.

L

• Load Time: The average time that it takes for a page to show up on your screen.

M

• Maintenance: A set of actions after the launch of a website to maintain the product.
• Metadata: Structured reference data that sorts attributes of specific information.
• Meta Tag: Information about web pages or elements like how a piece of content should be displayed or an image credit - this helps with SEO.
• Minification: The process of removing unnecessary characters from code files — such as whitespace, comments, and line breaks — to reduce file size and improve website performance.
• Mobile-first: Designing a website with this approach keeps the version for mobile devices in mind.

N

• Navigation: On a homepage, the links that break down website pages and showcase a journey for users. This can be through a menu at the top or bottom of a website. 

O

• Open Source: Software code that’s designed to be publicly accessible.
• Operating System: The program that manages all other applications and systems.
• Optimization: The process of improving website performance across various areas.

P

• Performance: Measurements related to the loading and operation of a website.
• PHP: A widely-used open source scripting language that embedded into HTML elements.
• Pixel: The smallest building block of graphical display on a web screen.
• Plugins: Modules that can be added to a system that bring additional features or functionalities.
• Programming Language: A system of notation for computer programs that can be text-based or graphical.
• PWA (Progressive Web Application): A type of web application that uses modern web features like offline caching, push notifications, and installable icons to deliver an app-like experience directly through the browser. PWAs work across devices and don’t require app store installation.

Q

• QA (Quality Assurance): The process that ensures that all aspects are error-free.

R

• Redirects: Automatic forwards from one URL to another.
• Responsive Design: A design approach that makes websites adjust to different screen sizes and devices. The same site should look and work well on a phone, tablet, or desktop without separate versions. Common techniques include flexible layouts, scalable images, and mobile-first design so users have a consistent experience no matter what device they use.

S

• Schema Markup: The code that can be used on a website to help search engines deliver more information to users.
• Screen sizes: The design and style for how a website is displayed on desktop or mobile.
• Scrolling: The act of moving a visual portion of a browser window vertically or horizontally.
• Scripting: A list of commands within a programming language.
• Search Engine: A huge database of internet resources where users can find what they’re looking for online.
• SEO (Search Engine Optimization): A set of practices that help a website rank higher in Google or other search engines. It includes improving site speed, ensuring mobile-friendliness, optimizing keywords and metadata, and organizing content so both people and search engines can navigate it. Strong SEO makes a site easier to discover and steadily increases traffic over time.
• Server-side: The side that houses the hosting for a website.
• Single Page Application (SPA): A web app that loads a single HTML page and updates content dynamically as users interact, instead of reloading the entire page. Frameworks like React, Angular, and Vue are often used to build SPAs.
• Sitemap: An outline of all pages on a website.
• Software stack: A group of tools and programs that work together to support an application. The lower layers often include the operating system and servers, while higher layers include databases, frameworks, and the interface users see. In web projects, a typical stack has four parts: front end, back end, database, and hosting. Common examples include the LAMP stack (Linux, Apache, MySQL, PHP) and the MERN stack (MongoDB, Express, React, Node.js). The stack you choose affects speed, cost, and long-term flexibility.
• SSG (Static Site Generation): A method of building web pages ahead of time into static files instead of generating them each time someone visits. Tools like Next.js, Hugo, and Gatsby use SSG so that when a user requests a page, the server simply sends a ready-made file. This makes sites faster to load, more secure (fewer moving parts on the server), and able to scale easily during traffic spikes.
• SSL (Secure Socket Layer): The standard technology for keeping an internet connection secure.
  Staging Site: A platform that contains the exact copy of the site that is used for testing and debugging.

T

• Template: The layout and design of the platform that can be replicated.
• Text Editor: One of the tools that websites use to add content to a page.

U

• Usability: The quality attribute for how easy a site is to use.
• User Experience (UX): How users describe feeling while navigating a website.
• User Interface: The point of human interaction within a website. For example, keyboard and mouse interactions on a web page.

V

• Version Control: A set of software tools that give web developers control over website changes.

W

• Web Address: Contains information about the location of the web page. Also known as the URL.
• WebAssembly (Wasm): A low-level binary format that allows code written in languages like C, C++, Rust, or Go to run in the browser with near-native performance. WebAssembly is often used for heavy tasks like graphics, video editing, or game engines.
• Web Browser: A program that allows users to locate and access web pages.
• Web Design: The process that focuses on the aesthetic features of a website.
• Web Pages: A document viewed in an internet browser.
• Web Performance Matrix: Measurements that track how fast and stable a website performs for users. Google’s Core Web Vitals are the primary benchmarks: Largest Contentful Paint (LCP) for load speed, Cumulative Layout Shift (CLS) for visual stability, and Interaction to Next Paint (INP), which replaced First Input Delay (FID) in 2024, for responsiveness.
• Web Server: A software and hardware that uses HTTP to respond to a client’s request online.
• Widgets: Small components that can be added to a web page to provide specific functions, such as a contact form, calculator, or social media feed. Widgets add interactivity without requiring developers to build everything from scratch.
• Wireframe: A layout that outlines the specific size and placements.
• WordPress: A popular, open-source CMS to build websites.
• WYSIWYG  (What You See Is What You Get): An editor that lets users design or edit content visually so it appears on screen much like it will once published. WYSIWYG tools are common in website builders and CMS platforms, such as the WordPress block editor.

Understand the Components of Web Development to Help Your Business

Web development can be a complex and intimidating technology field. There are many different aspects to consider, from server architectures and coding languages, to design techniques and user experience. 

This glossary has provided basic definitions for some of the most common terms used in web development, allowing readers to gain a better understanding of the topics involved. 

With this knowledge in hand, users can begin to explore the world of web development and create innovative websites that meet their needs.

How Clutch Can Help

Choosing the right development partner doesn’t have to be overwhelming. On Clutch, you’ll find vetted web development companies of all sizes and specialties, complete with verified reviews, service details, and industry focus areas.

Our platform makes it simple to:

• Compare vendors: Filter by expertise, location, or budget to find the right fit.
• Evaluate experience: Read detailed case studies and client reviews that show how teams deliver results.
• Build with confidence: Use our rankings and data-driven insights to create a trusted shortlist.

Pair this glossary with Clutch’s vendor data, and you’ll have both the language and the tools you need to make smarter, faster project decisions.

Frequently Asked Questions

What are the most important web development terms for beginners to learn first?

Start with HTML, CSS, JavaScript, front end vs. back end, and responsive design. Add a few “stick-with-you” fundamentals: how HTTP works (methods, headers), basic networking (TCP/UDP, ports), what a browser does to load a page, and accessibility. Include security basics (XSS, SQL injection — see OWASP Top 10) and a quick grasp of databases (relational vs. document). Knowing performance terms (Core Web Vitals, caching/CDN) and DNS basics helps in real projects. If you have time, learn version control (Git) and the idea of system design — they pay off early.

What’s the difference between front-end, back-end, and full-stack development?

• Front end is the user-facing layer: layout, visuals, and interactions in the browser or app (think HTML, CSS, JavaScript, accessibility, and performance across devices).
• Back end is the server side: APIs, databases, authentication, and business logic (reliability, scale, and cost control). Press “Play” on Netflix: the front end shows the catalog and player; the back end streams video, tracks your account, and serves recommendations.
• Full stack spans both, shipping an end-to-end feature (UI + API + data). It’s common in smaller teams and prototypes; larger orgs still value cross-stack fluency even if roles specialize.

Which new web development technologies should I know about in 2025?

Here’s a quick, buyer-friendly snapshot of what’s worth learning now — and why it matters for speed, scale, and UX:

• Jamstack & Edge Rendering: Pre-rendered sites with on-demand server functions, deployed to CDNs for faster global loads and simpler ops.
• Serverless & Managed Backends (FaaS/BaaS): Cloud functions plus auth/storage/queues to cut infra work and scale per request.
• Micro-frontends: Break big UIs into independently deployable pieces so large teams ship without collisions.
• WebAssembly (Wasm): Run C/C++/Rust in the browser for heavy compute like editors, codecs, crypto, and analytics.
• PWAs (Progressive Web Apps): Installable web apps with offline caching and push for reliable mobile and field use.
• AI web optimization: Copilots for dev speed and product features like semantic search or assistants via embeddings/RAG.

Are these web development terms relevant for non-developers, like project managers or business owners?

Yes. These terms help non-developers run better projects. A shared vocabulary cuts miscommunication, speeds approvals, and leads to smarter vendor decisions.

How often do web development terms change or get updated?

Foundations (HTML/CSS/JavaScript, HTTP, DNS) change infrequently; frameworks, hosting patterns, privacy rules, and performance metrics evolve regularly.

About the Author

Anna Peck Content Marketing Manager at Clutch

Anna Peck is a content marketing manager at Clutch, where she crafts content on digital marketing, SEO, and public relations. In addition to editing and producing engaging B2B content, she plays a key role in Clutch’s awards program and contributed content efforts. Originally joining Clutch as part of the reviews team, she now focuses on developing SEO-driven content strategies that offer valuable insights to B2B buyers seeking the best service providers.

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