Drag components onto a canvas, wire up the architecture, and get instant rule-based feedback. No code required.
Choose from real interview-style prompts, from URL shorteners to payment systems.
Drag components onto the canvas and connect them into an architecture.
A rule-based grader checks your design and tells you exactly what's missing.
Design a service like bit.ly that shortens long URLs and redirects on lookup.
Design a rate limiting service shared across multiple API instances.
Design a system that serves a personalized home feed, like Twitter's timeline.
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