Explore HTTP by connected concepts
Recurring topics bring together lessons, history, exact protocol lookups, diagnostic paths, and controlled observations. Specialized topics remain available in a compact index instead of becoming walls of repeated cards.
caching
17 reviewed entries- Reference304 Not Modified
- TroubleshootA conditional request does not return 304
- TroubleshootA page still looks stale after deployment
- GlossaryCache validator
- ReferenceCache-Control field
- ReferenceETag field
- GlossaryFreshness lifetime
- HTTP HistoryHTTP/1.0: when the growing Web needed real messages
- HTTP HistoryHTTP/1.1: persistent connections and the architecture of scale
- Referencemax-age cache directive
- Referenceno-cache cache directive
- LabObserve cache freshness
- LabObserve ETag revalidation
- ReferenceQUERY method
- LearnUnderstand HTTP caching and validation
- LearnUse the HTTP QUERY method for safe requests with content
- ReferenceVary field
fields
16 reviewed entries- ReferenceAccess-Control-Allow-Origin field
- ReferenceCache-Control field
- LearnConnect HTTP fields to representations
- ReferenceContent-Type field
- ReferenceCookie field
- ReferenceETag field
- TroubleshootHTTP fields change behind a proxy or CDN
- ReferenceLocation field
- LabObserve a bounded HTTP request
- LabObserve fixed response headers
- ReferenceOrigin field
- LearnParse modern HTTP fields with Structured Fields
- LearnRead HTTP messages without guessing
- GlossaryRepresentation
- ReferenceSet-Cookie field
- ReferenceVary field
methods
13 reviewed entries- TroubleshootA request method changed after a redirect
- LearnChoose an HTTP method by its semantics
- LabCompare methods across redirects
- ReferenceGET method
- ReferenceHEAD method
- GlossaryIdempotent method
- LabObserve a bounded HTTP request
- LabObserve an HTTP QUERY request
- ReferencePOST method
- LearnPredict HTTP redirects and method handling
- ReferenceQUERY method
- GlossarySafe method
- LearnUse the HTTP QUERY method for safe requests with content
CORS
11 reviewed entries- TroubleshootA browser reports a CORS error
- TroubleshootA CORS preflight request fails
- ReferenceAccess-Control-Allow-Origin field
- GlossaryCORS preflight request
- LabObserve a CORS preflight
- LabObserve an HTTP QUERY request
- LabObserve fixed response headers
- GlossaryOrigin
- ReferenceOrigin field
- ReferenceQUERY method
- LearnUnderstand the browser CORS flow
browsers
9 reviewed entriesdiagnostics
9 reviewed entries- TroubleshootA browser does not send a cookie
- TroubleshootA browser reports a CORS error
- TroubleshootA conditional request does not return 304
- TroubleshootA CORS preflight request fails
- TroubleshootA page still looks stale after deployment
- TroubleshootA redirect keeps repeating
- TroubleshootA request method changed after a redirect
- LabFollow a bounded redirect chain
- TroubleshootHTTP fields change behind a proxy or CDN
status codes
8 reviewed entriesmessages
7 reviewed entriesredirects
7 reviewed entriesHTTP history
6 reviewed entries- HTTP HistoryFrom a CERN information problem to HTTP/0.9
- HTTP HistoryHTTP/1.0: when the growing Web needed real messages
- HTTP HistoryHTTP/1.1: persistent connections and the architecture of scale
- HTTP HistoryHTTP/2: multiplexing the same Web semantics
- HTTP HistoryQUIC and HTTP/3: changing the transport beneath HTTP
- HTTP HistoryWhat HTTP's history teaches about protocol evolution
representations
6 reviewed entriescookies
5 reviewed entriesintermediaries
5 reviewed entriesorigins
5 reviewed entriesrequest content
5 reviewed entriesfreshness
4 reviewed entriespreflight
4 reviewed entriesproxies
4 reviewed entriesstandards updates
4 reviewed entriesCDN
3 reviewed entriesconditional requests
3 reviewed entriessafety
3 reviewed entriesstructured fields
3 reviewed entriesvalidators
3 reviewed entriesSpecialist index
Topics with one or two focused entries
These narrower concepts are still reviewed and searchable. They are grouped compactly until the corpus has enough distinct coverage to make each one a broader cluster.