When should I use leaky bucket instead of token bucket?
Leaky bucket (a queue that drains at a fixed rate) smooths output perfectly but adds latency and memory overhead. Use it for jobs that can queue (e.g., image resizing). Token bucket is better for synchronous APIs where excess traffic must be rejected immediately—it absorbs small bursts while respecting the limit.
Answered in
Token Buckets: Bounding Rate Limits at the EdgeFixed-window counters leak at boundaries. Token buckets refill steadily, absorb bursts, and bound the sustained rate strictly—the algorithm Stripe uses.
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