Design a distributed rate limiter

Intermediate50 minBuilds Distributed API Rate LimiterRead first: 3.2 What one machine can do, 1.3 Everything is a trade-off

STEP 1 OF 11

The brief

Your company runs a public API. Some customers send far more traffic than their plan allows, and one buggy script recently took the API down for everyone. You are asked to add rate limiting: each API key gets a number of requests per minute on each route, and anything above that is rejected.

What it must do

Enforce limits like 100 requests a minute per API key per route, across every API server.
Reject over-limit requests with 429 Too Many Requests and a Retry-After header.
Add almost no latency, since the check runs on every request.
Let operators change limits without a deploy.

How big it is

Requests checked: 11,000 / second
API servers: many, behind a load balancer
p99 goal for the whole request: under 100 ms

All changes saved

0 components · 0 connections

A blank canvas. A better system.

Add components from the palette, then drag between them to connect the request and event flow.

React Flow

Design a distributed rate limiter

Intermediate50 minBuilds Distributed API Rate LimiterRead first: 3.2 What one machine can do, 1.3 Everything is a trade-off

STEP 1 OF 11

The brief

What it must do

Enforce limits like 100 requests a minute per API key per route, across every API server.
Reject over-limit requests with 429 Too Many Requests and a Retry-After header.
Add almost no latency, since the check runs on every request.
Let operators change limits without a deploy.

How big it is

Requests checked: 11,000 / second
API servers: many, behind a load balancer
p99 goal for the whole request: under 100 ms

All changes saved

0 components · 0 connections

A blank canvas. A better system.

Add components from the palette, then drag between them to connect the request and event flow.

React Flow