Database-backed billing service with migrations, provider boundaries, and webhooks.
Repositories
Rehearse against our curated sample repositories, or connect your own. Every exercise runs on a temporary copy.
CURATED SAMPLES
Queue-driven inventory reconciliation with retry and missing-value failures.
HTTP gateway with explicit error handling, timeouts, and health-check incidents.
Java application with transactional and null-contract failure paths.
ASP.NET identity boundary with null contracts and configuration faults.
Typed event consumer with Option handling and recovery scenarios.
Bring your own repository
Your source is copied to a temporary workspace, secrets are redacted, and the original is never modified.
- Redacted secrets
- Allowlisted commands
- Expiring workspaces
- Read-only source