Learn System Design by Building

Stop drawing boxes on whiteboards. Wire real components, write real logic, and validate with real test cases.

Start Solving Read the Docs

Drag and connect components — servers, databases, caches, queues — just like real architecture diagrams, but interactive.

Write handler logic in a simple C++-flavored language. No boilerplate, no frameworks — just the system design logic.

Your system runs in a simulation with virtual time. Step through events, inspect state, find bugs before they find you.

Every problem has test cases. Your solution passes or it doesn't — just like LeetCode, but for distributed systems.

Available Components

Client Load generator — sends requests, asserts responses

HTTP Server Route table + handlers written in SysLang

Database Relational storage with schema: Find, Insert, Update, Delete

Cache Key-value store with TTL: get, set, del, has

Load Balancer Round-robin distribution across multiple servers

Open Problems