How the web works
Browsers, servers, HTTP, DNS and APIs, explained.
Every time you open a page, scroll your feed or send a message, dozens of machines work together in a fraction of a second. This track shows you how: clients and servers, IP addresses and ports, DNS, URLs and HTTP, how browsers build pages from HTML, CSS and JavaScript, APIs and JSON, HTTPS, cookies and tokens, caching and CDNs, speed on slow networks, and the security rules that keep everyone safe.
You finish by following one tap in a small social app called Nova from your phone to the database and back. Nothing to install: just curiosity and a browser.
- Lessons
- 19
- Time
- 2 h
- Level
- Beginner
- Bronze open
- Silver open
- Gold locked
Ready to prove it?
Three exams are waiting: Bronze, Silver and Gold.
What you'll be able to do
- Explain, step by step, what happens between typing an address and seeing the page
- Read and write HTTP requests and responses, and call an API with curl and fetch
- Debug a page with your browser's developer tools
- Understand HTTPS, cookies, sessions and tokens well enough to keep users safe
- Make pages faster on slow networks with caching, CDNs and smaller downloads
- Describe how a typical web platform is built, from browser to database
The journey
1 Module 1Clients, servers and addresses
Who asks and who answers, how machines find each other with IP addresses and ports, and how DNS turns names into addresses.
0 / 42 Module 2Speaking HTTP
URLs, requests, methods, status codes and headers: the language browsers and servers share.
0 / 43 Module 3Browsers and APIs
How a browser turns HTML, CSS and JavaScript into a page, and how pages fetch JSON from APIs.
0 / 34 Module 4Security and signing in
HTTPS and certificates, cookies, sessions and tokens, the same-origin policy, CORS and why the server never trusts the client.
0 / 45 Module 5Speed and the big picture
Caching and CDNs, speed on slow networks, and how a whole web app fits together.
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