PrepGrind — Interactive System Design & DSA Interview Prep Playground

PrepGrind is a free, interactive playground for learning system design and data structures & algorithms (DSA). Build architecture diagrams on a drag-and-drop canvas, run a live traffic simulation to watch your system behave under load, and study real-world case studies with structured interview guides.

What you can do on PrepGrind

• Design architectures visually with load balancers, caches, databases, message queues, CDNs, microservices, and more.
• Run a live simulation engine with real-time metrics, traffic, and bottleneck analysis.
• Explore 33 real-world system design case studies and presets.
• Follow guided interview breakdowns: requirements, core entities, API design, high-level design, deep dives, and scaling.
• Practice DSA with animated, step-by-step algorithm visualizations and curated LeetCode-style problems.

Popular system design case studies

• Design a URL Shortener
• Design Instagram
• Design a Chat System
• Design Video Streaming (YouTube)
• Design a Ride-Sharing Platform (Uber)
• Design an E-Commerce Platform
• Design a Payment Gateway (UPI)
• Design a Notification System
• Design a Rate Limiter
• Design a Distributed Key-Value Store

DSA patterns covered

Two pointers, sliding window, fast & slow pointers, binary search, backtracking, dynamic programming, graphs (BFS/DFS, topological sort), trees, heaps, tries, monotonic stack and queue, prefix sums, and greedy algorithms — each with animated playback.

PrepGrind runs entirely in your browser, free, with no installation required. Loading the interactive playground…