A timed coding-exercise platform in active production use by Learn2Earn fellows in Abuja. Candidates write in a real editor against a real runtime, and the platform records enough to review how an answer was produced, not just what was submitted.
What it does
- A Monaco editor (the VS Code engine) with live Go execution through a custom Go microservice deployed on Render and secured by API key.
- Real-time anti-cheat monitoring: paste detection, focus-loss tracking, keystroke recording, and full typing replay for submission review.
- Autosave, multi-role auth, audit logging, CSV export and bulk user management across 11+ exercise types.
- CI on every pull request through GitHub Actions, with branch protection and Neon serverless PostgreSQL behind it.
Worth calling out
Executing untrusted code is the hard part
The runner is a separate service on a separate host with its own key, so a hostile submission can reach a sandbox rather than the application that holds candidate records.
The replay is the evidence
Paste detection alone catches nothing — someone can retype. Recording the keystrokes and replaying them is what distinguishes a person solving a problem from a person transcribing one.
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