For devs who’d rather be humbled than bored

Challenges that fight back

Free daily Rust reasoning puzzle
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Challenges

Learn by defending your logic

You don't just write code here. You explain your thinking. Each challenge puts you in real Rust situations like debugging ownership, lifetimes, and concurrency while the system asks why you made each choice. It's not enough to say "it works." You'll be pushed to reason like a senior engineer who can justify every decision. That's how you grow.
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Feedback

Get feedback that sharpens your reasoning

Every review gives you clear, actionable insight into your thought process. You'll see where your logic holds up and where it breaks down. It's not about passing or failing. It's about learning to think clearly under pressure, just like in real reviews.
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Tracker

Level up your reasoning, one challenge at a time

You'll build consistency through daily reasoning sessions that track clarity, speed, and understanding. Each challenge adds experience to your skill graph, revealing how your reasoning evolves over time. You'll see your level rise, your logic sharpen, and real proof that you're improving every day.
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Challenges for every level

Accessible to beginners, demanding for experts. Build confidence through measurable growth in reasoning and Rust fluency today.
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FAQs

Everything you need to know