HTTP foundations

Start here when a browser, cache, crawler, or proxy is receiving a response that needs to be explained. The series moves from representation and method semantics to caching, redirects, compression, and discovery.

A cache and an origin trading a validator string to decide whether a stored response is still fresh.

Validators decide whether a cached copy is still the answer

Conditionals are the cache’s second clock; a 304 means the stored copy is still the answer.

A client walking through the response metadata a live edge returns, from method to range and cache.

Read a live edge the way a client does

Walk a live origin from method to body to cache, and leave with checks you can reuse.