How it works

Start with a working codebase and a focused task. Write code, ask AI for help, and decide which changes belong in your solution.

Choose a scenario
Browse by topic, level, and skill. Read the assignment, choose your coding language, then select Interview or AI Interview with flexible or timed pacing. Six complete problems are free.
Explore the repository
Keep the rendered README beside your code, move between files, and resize the panes to fit your workflow. Run code and visible tests in the workspace as you make changes.
Ask, inspect, and decide
Write your own prompts to the AI assistant. When it proposes a patch, inspect the diff, edit the proposed code, or reject it. Your workspace only changes when you apply the patch.
Test your assumptions
Visible tests give you feedback while you work. Hidden tests run after submission to assess edge cases and requirements. Your verification process contributes to the evaluation.
Review and repeat
Finish without evaluation to keep your saved work, or submit for a report with test outcomes and engineering feedback. With Pro, revisit your session replay to inspect your decisions, then practice a related problem.

See what you take away

Your report connects the final result with how you tested, used AI, and made decisions.