Every popular software should have a Rate Limiter. It prevents DDOS attack, reduces cost and prevents servers from being overloaded. There are some tricky questions to be considered during implementation of Rate Limiter: Where to put Rate Limiter: client-side, server-side, gateway? Algorithms for rate limiting. There are many algorithms with pros and cons: Token bucket, Leaking bucket, Fixed window counter, Sliding window log, Sliding window counter. Your business needs will define the right algorithm.
Four standard steps for system design interview. However, I would think about them wider: as about four initial steps to design the software. Step 1. Understand the problem and establish design scope Step 2. Propose high-level design and get buy-in Step 3. Design deep dive Step 4. Wrap up The chapter 3 of the book discovers details about each step, good questions to ask (to think about), DO’s and DONT’s.