Stop Reading
You have read the blog posts. You have watched the videos. But when the interviewer says "Design a URL shortener," you freeze. ScaleDojo is the interactive system design lab where you drag real components, build real architectures, and get instant AI feedback on your design decisions.
No credit card required. Build your first architecture in 5 minutes.
What You Will Build
Practice the Exact Systems That Get Asked in Interviews
From URL shorteners to distributed message queues. Build the architectures that separate Senior from Staff engineers.
HLD Architecture Challenges
The Static App
Design a single server static application.
The 3-Tier Web App
Add database replication and user session management.
URL Shortener
Design a highly-available URL shortening service like TinyURL.
Rate Limiter
Design an API Rate Limiter to prevent DOS attacks.
Notification System
Design a scalable multi-channel notification engine.
Consistent Hashing
Implement load balancing and server ring partition.
Distributed Message Queue
Design a high-throughput partitioned messaging queue like Kafka.
Uber Driver Matcher
Design a low-latency driver matching service using geospatial indexing.
Pick any challenge and start building. Every design gets scored by AI with detailed architectural feedback.
Start Building FreeThree Steps to System Design Confidence
Go from theory to hands-on system design practice in minutes. No setup, no prerequisites.
1. Pick a Challenge
Choose from 288 real-world system design scenarios across HLD, LLD, API Design, and GenAI labs. Start with a URL shortener or go straight to designing a distributed message queue.
2. Build Your Architecture
Drag components onto an interactive canvas. Connect load balancers, databases, caches, and message queues. Make the same trade-off decisions you would face in a real system design interview.
3. Get AI Feedback
Submit your design and receive detailed AI-powered analysis on your architectural choices. Identify gaps, fix mistakes, and understand why senior engineers make different decisions.
Murphy's Lab:
If It Can Break, It Will
Building an architecture is only half the challenge. Knowing if it survives real-world failure is what separates good engineers from great ones. Murphy's Lab is a chaos engineering simulator built into every HLD system design challenge. Crash servers, spike traffic, sever connections, and watch your design respond under pressure in real time.
247ms
Latency
12.4%
Error Rate
842 rps
Throughput
Prove It On Your Profile
Earn your first verifiable system design certificate in under a week. Each comes with a unique credential ID, a public verification page, and one-click sharing to LinkedIn and X.
ScaleDojoCertificate of Achievement
HLD Architecture Foundations
This certifies that
Your Name Here
Demonstrated proficiency in core distributed system design patterns including load balancing, caching, database replication, and URL shortening architectures.
Levels Completed
12 / 12 (Act 1 & 2)
Credential ID
SD-A1B2-C3D4
Free to start. No credit card required.
One Skill. Permanent Value.
Most system design courses charge $39 to $99 per month for video lectures. ScaleDojo gives you hands-on practice with AI feedback for a fraction of that cost. System design knowledge compounds. Engineers who truly understand distributed systems earn more, lead more, and build better.
7-day full refund policy. No questions asked.
- Act 1 + Act 2: 12 HLD Architecture Levels
- 10 LLD Schema Design Missions
- 10 API Design Challenges
- GenAI: Primer Levels
- Global Leaderboard Access
- 20 Credits on signup + 5/day
- 15 Credits per referral
- 2 MYD Architectural Slots
- Everything in Explorer, plus:
- HLD Levels 13 to 40 unlocked
- 30 LLD Schema Design Missions
- 30 API Design Challenges
- GenAI: Acts 0 through 4
- 800 AI Credits instantly
- 15 MYD Architectural Slots
- AI-Powered Logic Analysis
- PRO badge on profile
- Everything in Pro, plus:
- All 288 levels across every lab
- 70 HLD + 50 LLD + 50 API + 50+ GenAI + 60 Forge
- 3,000 AI Credits instantly
- 50 MYD Architectural Slots
- Full AI Reviews & Hints
- ARCHITECT badge on profile
- Priority Support
Creators Are Talking About ScaleDojo
Independent tech creators sharing ScaleDojo with their communities.
Real Feedback from Engineers Who Practice Here
"One of the most valuable parts of ScaleDojo was the Wiki section and the origin files. Instead of just covering interview patterns, they helped me build a deep understanding of core system design concepts from the ground up. The content is well-structured, practical, and goes beyond surface-level explanations. Combined with the mentorship and interview preparation, it gave me the confidence to reason through system design problems rather than memorize answers. Highly recommended for anyone preparing for top-tier engineering interviews."
Still Have Questions?
Your Next System Design Interview Is Coming
Every pattern you will drag onto the canvas started as a real engineering decision. The HLD Origin Files trace 8 chapters and 60 years of system design history, so you understand why load balancers, caches, and consistent hashing exist before you ever place one.
Free to read. No signup required.
