Backend development

Stage 1 · Lesson 9 of 10

HTTP requests, responses and headers

Your language and how HTTP works

is a set of structured messages sent over that connection. A request has a method (what to do), a path (which thing), headers and sometimes a body. A has a , headers and a body.

HTTP headers are labelled notes about the message, and your backend depends on them. Host says which site is wanted, and Content-Type says what kind of data the body holds. Authorization carries login details.

Cache-Control and ETag control caching, and Cookie and Set-Cookie carry sessions, which is how a site remembers you. The best way to see all this is curl -v https://example.com. It prints the address it connects to and the TLS .

It then shows every request header, marked with >, and every response header, marked with <.

Common trapsending without Content-Type: application/json and then wondering why the server cannot read the body.

A question to check yourself, an AI practice session and 1 cheat sheet entry come with the full roadmap. Unlock

Resources for this stage

Start with· follow one of these

  • CoursePaid
    Grokking JavaScript Fundamentals

    Design Gurus · Beginner · $50

    JavaScript itself in a sensible order: scope, closures, promises and async code

  • GuideFree
    Node.js Learn

    OpenJS Foundation · Beginner

    Official guides on the event loop, async work, the http module and environment variables

Practise

  • Exercism

    Your language track: small exercises with free mentor feedback on idiomatic code

Keep handy

  • The TypeScript Handbook

    Read Everyday Types and Narrowing first, then keep it open while you write TypeScript

  • MDN Web Docs

    Read the HTTP overview, methods, headers and status code pages until they feel obvious

Also worth your time

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