Rate Limiter

The previous chapters have described the underlying technologies such as consistent hashing, ID generator, and now using these techniques we can develop a URL shortener that can generate 100 million URLs per day. Design consists of the following elements: API endpoints URL redirecting URL shortening Data model Hash functions: Hash + collision resolution vs Base-62 conversion Additional topics to consider: Rate limiter Web server scaling Database scaling Analytics Availability, consistency, and reliability These items are disclosed in a very interesting Chapter 8 of the book:

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.