System Design Simulator

Beta

Build · Simulate · Master

Visually architect distributed systems, connect components, configure properties, and simulate traffic flow. Master system design interviews through hands-on building.

100+ Components13 ScenariosLive SimulationAuto-Save

My Designs

No designs yet

Create your first system design or start from a template below

Quick-Start Templates

6 templates

Pre-built architectures with real node graphs — open and customise

🌐
5 nodes

Simple Web App

Client → Load Balancer → Web Server → Cache + Database

4 connections
⚙️
9 nodes

Microservices

API Gateway → 3 microservices → Cache + DB + Queue

8 connections
🚀
5 nodes

CDN Architecture

Client → DNS → CDN → Load Balancer → Origin Server

4 connections
7 nodes

Event-Driven System

API Gateway → Event Bus → 3 async workers → Database

6 connections
🔄
6 nodes

Data Pipeline

Source → Message Queue → ETL Worker → Data Warehouse + Storage

5 connections
📡
7 nodes

Streaming Platform

API Gateway → Stream → Consumer → Cache + Database

6 connections

Scenario Challenges

13 total

Solve real system design problems with hints, scoring, and step-by-step guidance

🔗Beginner

URL Shortener

bit.ly — encode, decode, redirect at scale

HashingCachingRedirection
🏆Beginner

Real-Time Leaderboard

Live rank updates for millions of players

RedisWebSocketsSorted Sets
💬Intermediate

Real-Time Chat App

WebSocket fan-out with persistent message history

WebSocketsFan-outStorage
🎬Intermediate

Video Streaming

Upload, transcode, and stream video at scale

CDNTranscodingObject Storage