HTTP Semantics

Methods, status codes, headers and caching — the contract every web system speaks.

6 concepts · 215 minutes

• 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.
• 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.
• 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.