System Design
Demystified

Master the art of architecting scalable, reliable, and efficient systems. Interactive guides, simulations, and real-world case studies.

Core Building Blocks

Click a card to explore fundamental concepts with interactive diagrams.

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Scalability

Vertical (Scale Up) vs Horizontal (Scale Out). How to handle growth effectively.

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Load Balancing

Distributing traffic across multiple servers to ensure reliability and performance.

bolt

Caching

Speed up your system by storing frequently accessed data in fast memory.

VS
database

SQL vs NoSQL

Structured vs Flexible data. When to use a Relational DB vs a Key-Value store.

C A P
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CAP Theorem

Consistency, Availability, Partition Tolerance. You can only pick two.

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Async Queues

Decoupling systems using producers and consumers for asynchronous processing.

System Architect Simulator

Design a system to handle the traffic load without crashing.

Users
100
Latency
ERR
Status
OFFLINE

Infrastructure

group
Users
warning System Offline! Add a Server.

Real World Case Studies

Apply your knowledge to common interview questions. Detailed breakdown included.

speed

Design a Rate Limiter

Protect APIs from abuse and overload

check_circle Requirements

  • • Limit users to X requests per minute/second.
  • • Should function in a distributed environment (multiple servers).
  • • Low Latency (Check needs to be extremely fast).
  • • Return HTTP 429 (Too Many Requests) when blocked.

Core Algorithms

Token Bucket

A bucket holds 'tokens'. Tokens are added at a fixed rate. Each request consumes a token. No token = Request Dropped.
Good for burst traffic.

Sliding Window Log

Track timestamp of every request. Count requests in the last time window.
Very accurate, but high memory cost.

Redis Implementation Strategy Fastest

Since we need speed and distributed counting, Redis (In-Memory DB) is the industry standard solution.

INCR user_ip_timestamp
// Increment counter for this user+minute
EXPIRE user_ip_timestamp 60
// Auto-delete after 60 seconds
IF result > LIMIT THEN
  return HTTP 429