Stage 1 · Lesson 1 of 8
How a request reaches a server
Everything in this roadmap sits on one loop: the browser asks, and a server answers. When you type a web address, the browser first does a lookup, a phone book for websites that turns the name into an . It then opens a TCP connection, and for HTTPS a TLS handshake sets up (the S means secure).
Then it sends an HTTP request. The request has a method that says what it wants to do: GET to read, POST to create, PUT or PATCH to change, DELETE to remove. It also names a path (which page or data), carries (extra details) and sometimes a body of data.
The server replies with a , headers and a body, such as HTML or JSON. Learn the status code families now. 2xx means it worked, 3xx means go elsewhere, 4xx means the client got it wrong and 5xx means the server failed.
You will build both ends of this loop. Every later bug is easier once you can read it in the browser's Network tab.
A question to check yourself, an AI practice session and 2 cheat sheet entries come with the full roadmap. Unlock
Resources for this stage
Start with· follow one of these
- CoursePaidGrokking JavaScript Fundamentals
Design Gurus · Beginner · $50
Guided course on the language core if you want structure and quizzes
- CourseFreeThe Odin Project
The Odin Project · Beginner
Free Foundations course: HTML, CSS and JavaScript built in your own editor
Practise
Keep handy
Also worth your time
The request path from browser to server that the rest of this roadmap builds on