Systems Design Interview.
Your interview operating system. Look up concepts, estimate scale, compare databases, study real architectures, and practice mock interviews — all in one place.
Content Library
21Concepts
3Architectures
10Databases
6Protocols
8Auth Methods
6Caching Strategies
6Calculators
6Case Studies
8Mock Questions
12Crypto Terms
Quick Actions
Browse Concepts
Search the knowledge base with progressive depth levels
Design Studio
PEDALS-guided system design walkthroughs
Scale Lab
Back-of-the-envelope estimation calculators
Browse Architectures
Reference architectures for real-world systems
Database Studio
Compare databases and explore CAP tradeoffs
Mock Interview
Practice with timed sessions and progressive hints