Web & Networking

How a request actually crosses the internet, and the protocol everything else is built on.

14 concepts · 465 minutes

• JSON & SerializationThe lingua franca of APIs, plus the sharp edges: dates, big integers, and undefined.
• HTTP: Requests & ResponsesA stateless text protocol — understand its shape and half of backend work stops being mysterious.
• Methods & Status CodesGET/POST/PUT/PATCH/DELETE and what your API is really telling the caller with 201 vs 204 vs 202.
• How the Web WorksThe 200ms journey from typing a URL to seeing pixels — the map every other web topic hangs off.
• REST API DesignResources, not verbs — designing an interface another team can use without asking you questions.
• CORSThe browser rule that blocks your fetch — and why disabling it is the wrong fix.
• PaginationOffset vs cursor — and why page 5000 of your admin table times out.
• Headers, Cookies & StateHow a stateless protocol fakes memory — and where every auth bug you'll ever hit lives.
• CDNs & the EdgeMove the bytes closer to the user — the highest-leverage latency fix available.
• DNSA globally distributed, aggressively cached phone book — and the reason your deploy 'didn't work' for 20 minutes.
• GraphQLLet the client ask for exactly what it needs — and inherit a whole new class of problems.
• HTTP CachingCache-Control, ETags, and revalidation — the cheapest performance win that exists.
• Sessions vs JWTsTwo ways to remember who's calling, with genuinely different failure modes — especially logout.
• TLS & HTTPSWhat the padlock actually guarantees — and the three things it does not.