Sliding Window

A rate limiting algorithm that tracks requests in a rolling time window. More accurate than fixed windows because it smooths out spikes at window boundaries.

Sliding Window is a intermediate-level concept that sits in the Security Architecture area of system design. Engineers reach for it whenever they need to reason about real-world trade-offs in that space — not just for textbook correctness, but because real production systems at companies like Netflix, Amazon, and Google make these decisions every day.

If you want to go deeper than this definition — with diagrams, code, and a quiz to lock it in — work through the "Sliding Window" lesson linked below. It walks through the why, the mechanism, the trade-offs, and how the giants actually use it in production.