Learn system design through consequences

Stop reading about
architecture.
Start building it.

Daily micro-challenges + interactive simulations that show you the real consequences of architectural decisions. Built for engineers who want to think like architects.

Free forever for 5 questions/day

Daily Micro-Challenges

5 adaptive questions per day targeting your weakest skill areas. Answer twice to confirm — instant feedback with real explanations.

Architecture Simulations

Make real decisions for a URL shortener at scale. See your choices animate through a live system diagram with cascading consequences.

Skill Map

Track your growth across 6 skill areas: Database, Caching, Scalability, Security, API Design, and Reliability.

6 skill areas. Real consequences.

🗄️
Database
When does Redis lose data?
Caching
What causes cache stampede?
📈
Scalability
Horizontal vs vertical — when?
🔒
Security
IDOR, JWT expiry, info leakage
🔌
API Design
Idempotency keys, REST vs GraphQL
🛡️
Reliability
Circuit breakers, SLA math

Join engineers who think in systems

Start with 5 free questions per day. Upgrade for unlimited access, full simulation library, and AI-powered thinking evaluation.