Rate Limiting : Understand in 3 Minutes

Problem Statement Rate limiting is a technique that controls how many requests a user or system can make to a server within a specific timeframe. You encounter this problem directly when an API rejects your request with an error like "429 Too Many Requests" or "Rate Limit Exceeded." It affects you whether you're consuming an API that's throttling your app's calls, or building a service that's being overwhelmed by too much traffic, a buggy loop, or even a malicious attack. Core Explanation Think of rate limiting like a leaky bucket. A new, empty bucket can hold a certain number of tokens (your request allowance). Every time you make a request, you take a token out. Tokens leak back in at a steady rate (your replenishment rate). If you try to make a request when the bucket is empty, you’re denied until a token leaks back in. Under the hood, a simple rate limiter checks three key things for each incoming request: Who: It identifies the requester using an API key, IP address, or user ID. H