Buildex – Interactive system design practice with AI feedback

Hacker News

Hey HN, I built Buildex (https://buildex.dev) to help engineers practice system design interviews interactively. The problem: System design prep usually means reading blogs or watching videos passively. There's no way to actually practice designing systems and get feedback. How it works: - Pick a challenge (URL shortener, rate limiter, chat system, etc.) - Drag-and-drop components onto a canvas to design your architecture - Connect them to show data flow - Submit and get scored on efficiency, cost, and reliability - AI evaluates your design and gives specific feedback Tech stack: - Frontend: React + Vite - Backend: Go - Database: PostgreSQL - AI: Claude API for design evaluation - Payments: Razorpay Free tier gives you 2 AI evaluations/day. I'm a solo dev and built this over the past few months while prepping for interviews myself. Would love feedback on: - Challenge difficulty/variety - Scoring system fairness - UI/UX issues - What's missing? Happy to answer any questions about the implementation.

Visit product View on Hacker NewsDec 27, 2025

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nativeThis product was originally launched on this platform.

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