Rate Limiting 101: How to Protect Your APIs at Scale

How Systems Protect Themselves from Too Many Requests Modern systems don’t fail because they are badly written. They fail because they receive more requests than they can safely handle . Whether it’s an API, a backend service, or a public-facing platform, uncontrolled traffic can lead to: High latency Resource exhaustion Cascading failures Complete downtime This is why rate limiting  exists. At a high level, rate limiting answers one simple question: How many requests should we allow, and when should we say “no”? In this article, we’ll take a simple and intuitive approach to understand the most common rate limiting strategies used in real systems. For each strategy, we’ll look at: How it works conceptually Its strengths and weaknesses When it should be used A small JavaScript example to see it in action Rate Limiting 101 What Is Rate Limiting, Really? Rate limiting is not about blocking users. It is about protecting systems . Instead of letting traffic grow uncontrollably, rate limitin