Foundations
What a website is made of: domains, hosting, browsers and the languages every page is written in.
API
An API is a defined way for one piece of software to ask another for data or actions, such as a site asking a payment service to charge a card.
Back-end
The back-end is the server-side part of a site that visitors never see: databases, logins, payments, business logic and the APIs the front-end calls.
Cache
A cache is a stored copy of something, like a page or image, kept closer to the visitor so it loads instantly next time instead of being fetched again.
CDN
A CDN is a network of servers around the world that keeps copies of a site's files and serves each visitor from the location nearest to them.
CMS
A CMS is software that lets people create and edit website content through an admin screen instead of editing code.
Cookie
A cookie is a small piece of data a website stores in the browser to remember something between visits, like a login or a cart.
CSS
CSS is the language that controls how a web page looks: colours, fonts, spacing, layout, animation and how the design adapts to each screen.
Database
A database is organised storage for a site's data, such as users, orders and posts, that the back-end reads and writes on request.
DNS
DNS is the internet's address book: it translates a domain name like example.com into the IP address of the server that hosts the site.
Domain name
A domain name is the human-readable address of a website, such as example.com, that points to the server where the site lives.
Dynamic site
A dynamic site builds each page on the server when it is requested, so it can show personalised or constantly changing content.
Favicon
A favicon is the small icon shown in browser tabs, bookmarks and search results that identifies a website at a glance.
Front-end
The front-end is everything that runs in the visitor's browser: the layout, styling, content and interactions of a website or app.
Full-stack
Full-stack describes work, or a developer, that covers both the front-end a visitor sees and the back-end that stores data and runs the logic.
Homepage
A homepage is the main page at a website's root address, the page that tells a new visitor what the site is and where to go next.
HTML
HTML is the language that gives a web page its structure: headings, paragraphs, links, images, forms and every other element on the page.
HTTP and HTTPS
HTTP is the protocol browsers and servers use to exchange web pages; HTTPS is the encrypted version, shown by the padlock, and is now the default for every site.
JavaScript
JavaScript is the programming language of the web: it runs in every browser and makes pages interactive, from menus and forms to games and 3D.
JSON
JSON is a lightweight text format for structured data, readable by people and machines, and the standard way web APIs send information.
Landing page
A landing page is a single page built for one goal, such as a sign-up or a purchase, usually the page a visitor lands on from an ad or campaign.
PWA
A PWA is a website that can be installed to a phone or desktop home screen and can work offline, behaving much like a native app.
Responsive design
Responsive design is building one website whose layout adapts to every screen size, from phones to wide monitors, instead of separate mobile and desktop sites.
Sitemap
A sitemap is a list of a website's pages: an XML file for search engines, or a page of links for people, that shows what exists and how it is organised.
Static site
A static site is made of pre-built HTML files served the same way to every visitor, which makes it fast, cheap to host and hard to break.
URL
A URL is the full address of one specific resource on the web, made of a protocol, a domain and a path, like https://example.com/pricing.
Web app
A web app is software that runs in the browser and lets people do things, such as edit, book, chat or buy, rather than only read.
Web browser
A web browser is the app that requests web pages and turns their HTML, CSS and JavaScript into what you see and click.
Web hosting
Web hosting is the service that stores a website's files on internet-connected servers and delivers them to visitors around the clock.
Web page
A web page is a single document on the web, identified by its own URL and written in HTML, that a browser renders for a visitor.
Web server
A web server is software, and the computer running it, that receives requests from browsers and responds with web pages and files.
Webhook
A webhook is an automatic message one service sends to your URL when something happens, like a payment provider announcing a completed order.
Website
A website is a collection of linked web pages published under one domain name, stored on a server and viewed in a web browser.