Rate Limiter Simulator — Interactive System Design Lab

Send bursts of traffic and watch the token bucket algorithm accept requests while tokens are available and drop them when the bucket is empty. Tune the refill rate and bucket size to see how smoothing behaviour changes — and understand why token buckets are the most common rate limiter in production APIs.

Send traffic bursts and watch the token bucket accept or drop requests in real time.

This free interactive simulation runs directly in your browser — no account needed. Adjust the parameters and watch how the system responds in real time.

Concepts covered

  • rate limiter
  • token bucket
  • API throttling
  • traffic shaping
  • burst limiting
  • request throttling

Read the guide

  • Performance Antipatterns — You can use the fastest language and the biggest server, but bad design will still kill you. Learn how to spot the 'N+1', the 'Sync Chain', and the 'God Object'.
  • API Gateway — The bouncer, the receptionist, and the translator. It decouples your messy backend microservices from the clean public-facing API.

Related articles

  • How to Answer Any System Design Question — A step-by-step framework for tackling any system design interview question — requirements, estimation, high-level design, and deep dives — with a full worked example (Design a URL shortener) and the phrases interviewers listen for.
  • Top 10 System Design Interview Questions — The most frequently asked system design interview questions — URL shortener, rate limiter, key-value store, news feed, chat, and more — with the approach, key trade-offs, and follow-up questions interviewers actually ask for each one.