api design

Everyone names token bucket. The scored part is the rest: drift between nodes, the 429 contract with clients, and whether your quota service should fail open or closed.

Timeouts guarantee uncertainty, not failure: the first request may have succeeded after the client gave up. The idempotency key pattern is the industry answer; the scored details are storage, expiry and concurrency.

The most rehearsed design question, which is exactly why the interesting parts are the ones blog posts skip: redirect semantics, key generation under failure, and analytics kept off the hot path.