Token Bucket

A rate limiting algorithm where tokens are added to a bucket at a fixed rate. Each request consumes a token; requests are rejected when the bucket is empty. Allows short bursts.

Token Bucket 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 "Token Bucket" lesson linked below. It walks through the why, the mechanism, the trade-offs, and how the giants actually use it in production.