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Built Cognisia — an AI powered practice tool for system design interviews

Hey Indie Hackers đź‘‹

I just launched Cognisia (https://cognisia.app), a system design interview practice tool focused on how you explain your thinking, not just what you know.

Most prep today is reading blogs or watching videos, but interviews evaluate clarity, structure, and trade-offs under pressure. Cognisia lets you:

  • practice answering real system design questions out loud

  • get structured AI feedback on clarity, structure, and reasoning

  • follow guided learning paths to know what to study next

It’s live in beta right now and still evolving, but I wanted to share it with this community as I start collecting early feedback and usage patterns.

Would love thoughts from folks who’ve been through system design interviews:

  • Does spoken practice resonate?

  • What would make something like this part of your regular prep?

Happy to answer any questions.

posted to Icon for group Startups
Startups
on December 31, 2025
  1. 1

    Really cool — system design interviews are such a pain point for many engineers, and an AI-powered practice tool could really help people build intuition and get feedback without needing a live partner.

    One thing I’ve noticed with learning tools like this is that feedback quality vs speed often makes or breaks early user retention — people will trade longer wait times for useful, actionable explanations rather than just quick outputs.

    Curious — what’s been the biggest signal from early users so far: improved confidence, better performance in real interviews, or just more practice consistency? That distinction often shapes the next feature priorities.

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