Free course

HTTP Course

Learn how HTTP requests and responses work, including methods, status codes, headers, caching, cookies, security, and modern versions.

7 modules · 31 lessons · No signup

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What you'll learn

Inspect an HTTP exchange and reason about its method, status, headers, body, and browser behavior.

Course contents

  1. From a URL to a response

    DNS, connections, clients, servers, requests, and responses.

    1. ✓ What HTTP does
    2. ✓ Clients and servers
    3. ✓ Read a URL
    4. ✓ Before the request
    5. ✓ Inspect the request cycle

  2. Requests

    Methods, paths, query strings, headers, and request bodies.

    1. ✓ Anatomy of a request
    2. ✓ HTTP methods
    3. ✓ Safe and idempotent methods
    4. ✓ Query strings and request bodies
    5. ✓ Send a request with curl

  3. Responses

    Status codes, headers, bodies, redirects, and failures.

    1. ✓ Anatomy of a response
    2. ✓ Status code families
    3. ✓ Success and redirects
    4. ✓ Client errors
    5. ✓ Server errors

  4. Headers and representations

    Describe and negotiate the content exchanged over HTTP.

    1. ✓ Request headers
    2. ✓ Response headers
    3. ✓ Content types and encodings
    4. ✓ Content negotiation

  5. Caching

    Freshness, validators, conditional requests, and cache scope.

    1. ✓ Why HTTP caching matters
    2. ✓ Cache-Control
    3. ✓ Validators and conditional requests
    4. ✓ Debug a cached response

  6. State and browser security

    Cookies, authorization, origins, CORS, and security headers.

    1. ✓ Cookies add state
    2. ✓ Sessions and bearer tokens
    3. ✓ Origins and CORS
    4. ✓ Browser security headers

  7. HTTPS and modern HTTP

    TLS, HTTP/2, HTTP/3, and practical protocol debugging.

    1. ✓ HTTPS and TLS
    2. ✓ From HTTP/1.1 to HTTP/2
    3. ✓ HTTP/3 and QUIC
    4. ✓ Final HTTP inspection