Rate limiting.

also: rate limiter · rate limiters · rate limit · rate limits · rate-limited

Capping how many requests a client may make per time window, and rejecting or delaying the excess.

the two-minute refresher

A contract: up to N requests per period T per key (API key, IP, user); beyond that, rejected until the period resets.
It protects you from abuse, runaway clients and cost blow-ups.
It lives at several layers: CDN/edge, API gateway, application.
Tell clients their state: 429 Too Many Requests plus limit/remaining/reset headers.

also: rate limiter · rate limiters · rate limit · rate limits · rate-limited

Capping how many requests a client may make per time window, and rejecting or delaying the excess.

A contract: up to N requests per period T per key (API key, IP, user); beyond that, rejected until the period resets.
It protects you from abuse, runaway clients and cost blow-ups.
It lives at several layers: CDN/edge, API gateway, application.
Tell clients their state: 429 Too Many Requests plus limit/remaining/reset headers.