dLeetCode — Learn System Design by Living ItdLeetCode is an interactive system design learning platform. Step into one of three career paths — Startup Founder, Big Tech Engineer, or Contract Developer — and make real architecture decisions in immersive, narrative-driven scenarios. Each decision teaches system design tradeoffs through consequences and insights.How It Works

Pick a career path — Startup Founder, Big Tech Engineer, or Contract Developer. Each path has unique challenges that mirror real-world roles.

Read the scenario — You're dropped into a realistic situation with context, constraints, and stakes. Your company, your system, your call.

Make your decision — Choose from architecturally meaningful options. There's no single right answer — every choice teaches you something about real tradeoffs.

See the consequences — Learn what happens when you pick PostgreSQL over DynamoDB at startup scale, or propose microservices to a 3-person team.

Career Paths

Startup Founder — 3 chapters, 9 scenarios. Build and scale a product from zero to product-market fit and beyond.

Big Tech Engineer — 3 chapters, 9 scenarios. Navigate large-scale distributed systems, oncall incidents, and cross-team design reviews.

Contract Developer — 3 chapters, 9 scenarios. Deliver client projects under tight deadlines with shifting requirements and real business constraints.

Why dLeetCode?

Learn by living, not cramming — Instead of reading about CAP theorem, experience what happens when your database goes down during a traffic spike.

Real tradeoffs, not toy problems — Every decision has pros and cons. Learn to think in tradeoffs, not absolutes.

Career-specific context — A startup founder and a Big Tech engineer face different constraints. Our paths reflect that.

27 scenarios, 108+ decisions — Covering caching, load balancing, database design, microservices, CDNs, autoscaling, and more.

dLeetCode is currently free for a limited time. Visit dleetcode.com to start learning.