🛒 E-Commerce

E-commerce (electronic commerce) is the buying and selling of goods and services over the internet. It is one of the most important applications of web programming — in 2024, global e-commerce sales exceeded $6.3 trillion USD.

📖 Key E-Commerce Concepts

Concept	What It Means	Example
Product catalogue	Database of all items with names, prices, images, stock levels	Amazon lists over 350 million products stored in databases
Shopping cart	Temporary storage of selected items, managed by cookies or server sessions	Adding Nike shoes to your Footlocker cart saves them until checkout
Payment gateway	Third-party service that securely processes credit card payments	Stripe, PayPal, Afterpay — the shop never sees your card number
SSL / HTTPS	Encryption that scrambles data between your browser and the server	The padlock 🔒 in your browser's address bar = HTTPS active
User accounts	Server-side storage of order history, addresses, wishlists	Your ASOS account remembers past orders and saved addresses

Security is critical. E-commerce sites handle credit card numbers, home addresses, and personal data. Web programmers must use HTTPS encryption (data is scrambled during transmission), password hashing (passwords are stored as unreadable codes), and payment gateways (the shop never handles raw card numbers — Stripe or PayPal does it for them). One data breach can destroy a business.