Fixed window counter.
also: fixed window · fixed-window counter · fixed window rate limitingCounting requests per fixed time slot (each minute) and resetting at the boundary; simple, but allows up to 2× bursts across a boundary.
the two-minute refresher
- One counter per key per window: INCR, and reject above the limit.
- Very cheap: one integer per key.
- Flaw: 100 requests at 00:59 and 100 at 01:00 pass a 100/minute limit, twice the rate.