Question 1

What is ScaleDojo?

Accepted Answer

ScaleDojo is the #1 interactive system design practice platform. Instead of reading theory, you build real distributed architectures by dragging and connecting cloud components, designing database schemas on an ER canvas, and crafting production REST APIs. It includes 70 HLD levels, 50 LLD missions, 50 API design levels, a global leaderboard, and a structured learning roadmap — all with AI-powered scoring and review.

Question 2

How do I practice system design?

Accepted Answer

The best way to practice system design is hands-on building. ScaleDojo lets you design architectures for real-world systems like URL shorteners, rate limiters, notification systems, and payment gateways. You drag cloud components (load balancers, databases, caches, message queues) onto a canvas, connect them with data flows, and get scored by a deterministic engine plus AI architect review. Start with the free HLD Architecture Lab at scaledojo.dev/lab.

Question 3

How is ScaleDojo different from other system design resources?

Accepted Answer

ScaleDojo is a doing platform, not a reading one. Unlike passive resources (books, videos, blog posts), ScaleDojo has an interactive canvas where you drag, connect, and deploy real architectures and get instant feedback. It features deterministic scoring across 5 dimensions, AI-powered architect review, global leaderboard rankings, and three distinct labs covering HLD, LLD (database schema design), and API design.

Question 4

What is the best system design course for beginners?

Accepted Answer

ScaleDojo is ideal for system design beginners because it teaches through progressive challenges. Start with Level 1 (The Static App) which introduces basic architecture concepts, then progress through increasingly complex systems. The structured roadmap guides you from fundamentals (DNS, load balancing, caching) through intermediate patterns (message queues, event-driven design) to advanced topics (distributed consensus, CQRS). Each level has clear missions and instant scoring.

Question 5

How do I prepare for a system design interview?

Accepted Answer

System design interview prep requires practice building actual systems, not just reading about them. ScaleDojo's 70 HLD challenges cover the most-asked interview topics: URL shortener, rate limiter, notification system, key-value store, chat system, news feed, video streaming, and more. Each challenge tests your understanding of scalability, reliability, latency, and cost trade-offs — exactly what interviewers evaluate.

Question 6

What labs does ScaleDojo offer?

Accepted Answer

ScaleDojo offers three interactive labs: (1) HLD Architecture Lab — 70 levels of high-level system design where you drag cloud components and build distributed architectures, (2) LLD Schema Design Lab — 50 database ER diagram missions where you model entities, columns, constraints, and relationships, and (3) API Design Lab — 50 levels of REST API design covering endpoints, HTTP methods, request/response schemas, error handling, pagination, and authentication.

Question 7

Is ScaleDojo free?

Accepted Answer

Yes! ScaleDojo has a free tier with 7 HLD architecture levels, 10 LLD schema design missions, 10 API design levels, and 10 AI review credits. You can try all three labs without signing up. Paid plans unlock more levels (up to 170+ total), additional AI credits, and features like Arena Mode.

Question 8

What is high-level design (HLD) vs low-level design (LLD)?

Accepted Answer

High-Level Design (HLD) focuses on the overall system architecture — which components to use (load balancers, databases, caches, queues), how they connect, and how data flows between them. Low-Level Design (LLD) zooms into individual components, particularly database schema design — defining entities, columns, data types, constraints, relationships, and normalization. ScaleDojo has dedicated labs for both: the HLD Architecture Lab (70 levels) and the LLD Schema Design Lab (50 missions).