Explainers: HTTP
Retry-After for 429 and 503: Build a Safer Client
Parse Retry-After correctly, then combine it with deadlines, jitter, attempt caps and idempotency checks.
Cache-Control: no-cache vs no-store vs private
Choose no-cache, no-store or private by what may be stored, reused and shared—not by the directive's name.
HTTP Content Negotiation: Accept, Content-Type and Vary
Use Accept, Content-Type and Vary correctly so APIs select representations without breaking shared caches.
ETag vs Last-Modified: Choosing an HTTP Validator
Choose the right HTTP validator for caching, conditional requests and safe concurrent updates.