Design a Rate Limiter

Medium

+200 XP

PRO

Low Level DesignLLDSystem DesignOOPStrategy PatternConcurrencyDistributed Systems

Design a rate limiting system that controls the number of requests users can make within a time window to prevent abuse and ensure fair resource usage. The system should support multiple algorithms (Fixed Window, Sliding Window, Token Bucket), work across distributed servers, and be configurable per user or API key. You'll implement thread-safe operations and the Strategy pattern for swappable rate limiting algorithms.

Config

Bucket Capacity

10 tokens

Refill Rate

1 / sec

Total Processed

0 OK0 Drop

TOKEN BUCKET

SERVER

What You'll Build

The system should limit the number of requests a user can make within a defined time window (e.g., 100 requests per minute).
The system should support multiple rate limiting algorithms: Fixed Window Counter, Sliding Window Counter, and Token Bucket.
Rate limits should be configurable per user, IP address, or API key.
When a rate limit is exceeded, the system should return an appropriate error response (e.g., HTTP 429) with information about when the limit will reset.
The system should track request counts and timestamps accurately to enforce limits.
...and more

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