All courses

Web Networking, HTTP & Automation

Learn what happens between a URL and a response, inspect it in browser DevTools, debug it with professional tools, and automate reliable web workflows. Twenty units with practical labs, from packets and TLS to APIs, browser automation, and responsible data extraction.

Part 01 of 6 · 6 chapters

Networking foundations

Follow a request from frames and addresses through DNS, transport, TLS, and HTTPS.

  1. Orientation, ethics, and the network benchfree to read3 h read · 2 h lab

    Map the course, set up a safe lab, define authorisation, and learn to preserve useful evidence without leaking secrets.

  2. Models, packets, frames, and physical realityfree to read4 h read · 2 h lab

    Connect OSI and TCP/IP models to bytes on a wire, Ethernet frames, ARP, MTU, bandwidth, latency, and loss.

  3. IP addressing, subnetting, routing, NAT, and portsfree to read5 h read · 3 h lab

    Read IPv4 and IPv6 addresses, reason about subnets and routes, and follow traffic through gateways, NAT, and firewalls.

  4. DNS and name resolutionfree to read4 h read · 2 h lab

    Trace recursive and authoritative DNS, inspect records and caching, and diagnose common resolution failures.

  5. TCP, UDP, sockets, and connection lifecyclefree to read4 h read · 3 h lab

    Understand handshakes, streams, datagrams, ports, socket state, retransmission, flow control, and timeouts.

  6. TLS, certificates, and HTTPSfree to read5 h read · 3 h lab

    Follow a TLS handshake, validate certificate chains and hostnames, understand SNI and ALPN, and debug HTTPS safely.

Part 02 of 6 · 4 chapters

HTTP in depth

Master requests, responses, state, authentication, caching, proxies, and protocol versions.

  1. URLs, requests, methods, and bodiesfree to read4 h read · 2 h lab

    Construct requests deliberately: URL components, methods, query strings, headers, body encodings, redirects, and idempotency.

  2. Responses, status codes, and representation formatsfree to read4 h read · 2 h lab

    Interpret response status, headers, bodies, content negotiation, compression, streaming, and error contracts.

  3. Headers, cookies, sessions, and authenticationfree to read5 h read · 3 h lab

    Work with HTTP metadata and state while handling cookies, credentials, API keys, Basic, bearer tokens, OAuth, and CSRF safely.

  4. Caching, proxies, CDNs, and protocol versionsfree to read5 h read · 3 h lab

    Reason about freshness and validators, forward and reverse proxies, CDNs, HTTP/1.1, HTTP/2, HTTP/3, and WebTransport.

Part 03 of 6 · 3 chapters

Browser laboratory

Investigate real behavior with the Console, Network panel, Fetch API, and browser security boundaries.

  1. Runtime, console, and Fetch APIfree to read4 h read · 3 h lab

    Use the browser as an HTTP workbench: console, fetch, promises, JSON, DOM inspection, copy-as-code, and safe experiments.

  2. Network panel and performance investigationfree to read4 h read · 3 h lab

    Read request details, initiators, timing waterfalls, cache behavior, throttling, HAR files, WebSockets, and service-worker effects.

  3. CORS, CSP, storage, and security boundariesfree to read4 h read · 3 h lab

    Understand origins, preflights, credentials, CSP, mixed content, cookie policy, storage, service workers, and why browsers block requests.

Part 04 of 6 · 3 chapters

Professional tools

Reproduce and inspect traffic with CLI clients, API workbenches, proxies, debuggers, and packet capture.

  1. curl, HTTPie, wget, and PowerShellfree to read4 h read · 3 h lab

    Reproduce requests outside the browser, inspect redirects and TLS, upload files, preserve sessions, and produce repeatable command-line evidence.

  2. API clients, specifications, and realtime protocolsfree to read4 h read · 3 h lab

    Use Postman, Insomnia, Bruno, and Hoppscotch; read OpenAPI; test REST, GraphQL, webhooks, SSE, and WebSockets.

  3. Proxies, packet capture, and HTTP debuggersfree to read4 h read · 3 h lab

    Choose and safely operate Burp Suite, OWASP ZAP, mitmproxy, Fiddler, Charles, Proxyman, HTTP Toolkit, Wireshark, tcpdump, and related tools.

Part 05 of 6 · 3 chapters

Automation & extraction

Build reliable Python, Node.js, browser, and responsible data-extraction workflows.

  1. Python HTTP workflowsfree to read4 h read · 3 h lab

    Build maintainable clients with requests and HTTPX: sessions, timeouts, retries, pagination, streaming, validation, concurrency, and tests.

  2. Node.js and browser controlfree to read4 h read · 3 h lab

    Automate with fetch and Undici, parse HTML, and use Playwright, Puppeteer, or Selenium when a real browser is genuinely required.

  3. Responsible data extraction and scrapingfree to read5 h read · 4 h lab

    Design resilient extraction around permission, APIs, robots directives, rate limits, semantic parsing, deduplication, provenance, and change detection.

Part 06 of 6 · 1 chapters

Production capstone

Ship an observable, bounded automation with tests, failure policy, telemetry, and an operator runbook.

  1. Reliability, observability, and capstonefree to read4 h read · 6 h lab

    Ship an observable automation: explicit contract, redacted logs, metrics, traces, tests, replay fixtures, failure policy, and an operator runbook.

Reference, always open beside you

  1. Snippetsfree to read

    Copy-paste-ready code, one file per snippet.

  2. Cheatsheetsfree to read

    Single-page quick reference cards.

  3. Worked examplesfree to read

    Full end-to-end crack walkthroughs.

  4. Checklistsfree to read

    Workflows and pre-flight lists.

  5. Referencefree to read

    Everything the units cross-link into.