The Runtime Theory
Backend EngineeringIn production

Rate Limiting Algorithms, Visualized

Recording in progress
#rate-limiting#api-gateways#algorithms

Rate limiters decide when to say no, and the algorithm behind the decision changes what bursts look like and how much memory the limiter needs. This video animates a token bucket refilling, a leaky bucket draining, and a sliding window advancing, then shows which algorithms real gateways run.

Topics covered:

  • Token bucket: refill rate, capacity, and burst behavior
  • Leaky bucket: the fixed-rate outflow queue
  • Fixed window: cheap but bursty at the boundary
  • Sliding window log vs counter: precision vs memory
  • Distributed limits: Redis counters and atomicity
  • What nginx, Kong, and Envoy actually use

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