Post

2/ There are exactly 5 algorithms you must know. I’ll give you the mental model, when to pick each, and the real trade-offs (the stuff interviewers actually test).

3/ 1. Token Bucket Tokens refill at a steady rate into a bucket. Each request grabs one. Run out? Block or queue. Superpower: Allows natural bursts (uploading 20 photos at once feels smooth). Real-world: Stripe, GitHub, AWS APIs. Pick this when your users are humans, not robots.

4/ 2. Leaky Bucket Requests pour in but only “leak out” to your servers at a fixed constant rate. Bucket fills up? Extra requests get dropped. Superpower: Perfectly smooth downstream traffic – your DB never sees spikes. Catch: Zero bursts allowed. Use when stability > flexibility.