Ledger & event-driven systems
CloudScale Backend
Keep ledger state correct when commands are retried and consumers restart.
Used transaction-bound idempotency, balanced postings, and a transactional outbox, with PostgreSQL and SQLite adapters behind shared contracts.
- Evidence
- PostgreSQL integration tests and an executable backup/restore drill that rebuilds derived state.
- Boundary
- Recovery measured at seeded scale; sustained availability is a target, not a demonstrated result.