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Show HN: I built an AI-powered technical interview prep tool (crackr.dev)
1 point by wa5ina 50 days ago | hide | past | favorite | 1 comment
LeetCode wasn't actually preparing me or anyone else for the pressure of a real technical interview.

Most platforms just give you a text box and a compiler. I wanted something that actually simulates the back-and-forth of an interviewer pushing you on time complexity, asking follow-up questions, and pointing out edge cases you missed.

> The Stack: I built the backend with nestjs, prisma, postgresql, Webrtc for real time back and forth conv and [socket.io](http://socket.io) events in panel like code run etc…. claude-haiku-4-5 for conv and anthropic.claude-sonnet-4-6 for interview scoring.

> Where it still falls short: It’s not perfect. Sometimes the AI gets overly pedantic about syntax instead of focusing on the core algorithmic logic. I’m still tuning the prompts to make it behave more like a senior engineer and less like a strict compiler.

I'm currently trying to stress-test the system. I’d love for you to try breaking the AI interviewer or tell me why this approach is flawed. Happy to answer any questions about the stack or the prompt engineering.



Hey HN, OP here. I built this because grinding raw LeetCode only teaches you how to pass test cases, not how to communicate. The AI interviewer is specifically prompted to interrupt you and ask 'why' if you start coding without explaining your approach first—just like a real senior engineer would. I'm still tuning how aggressive the interruptions are. Let me know if the pacing feels natural or annoying




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