Choose a challenge. Prove it.

Implement auth, message persistence, and live updates. Focus on correctness and clean architecture.

Profile a slow page and ship a measurable improvement. Bonus: explain the root cause clearly.

Create a well-validated endpoint with sensible error handling and a tidy schema.

Build a component with accessible interactions, states, and clean styling.

Protect an endpoint with a simple limiter. Handle edge cases and provide clear feedback.

Migrate data safely with rollback strategy. Emphasis on correctness and safety.